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What conditions are related to the anterior pituitary?

Several different conditions are related to issues with the anterior pituitary since it produces so many different hormones. In general, the majority of conditions related to the anterior pituitary are due to hypopituitarism (underactive pituitary gland) or hyperpituitarism (overactive pituitary gland). In these conditions, your anterior pituitary either produces too little or too much of one or more hormones.

Hypopituitarism and hyperpituitarism are generally caused by one of the following conditions or situations:

Pituitary gland tumors (adenomas).

Damage to your anterior pituitary, hypothalamus or pituitary stalk through injury, infection or blood loss.

Genetic conditions, such as multiple endocrine neoplasia (MEN).

Hypopituitarism conditions

Conditions that are the result of lower-than-normal levels of one or more anterior pituitary hormones include:

Secondary adrenal insufficiency: Usually, adrenocorticotrophic hormone (ACTH) signals your adrenal glands to make cortisol, an essential hormone. If your pituitary gland produces low levels of ACTH, it leads to an underactive adrenal gland. This is known as central or secondary adrenal insufficiency (not to be confused with Addison's disease, which is cortisol deficiency due to a primary adrenal gland problem).

Growth hormone deficiency: This condition happens when your anterior pituitary releases lower-than-normal levels of growth hormone (GH). A deficiency in GH in adults can cause changes in body composition due to changes in fat and muscle, unhealthy cholesterol levels and loss of energy. If GH deficiency in children leads to poor overall growth and short height.

Hypogonadism (low sex hormones): Hypogonadism occurs when sex glands don't produce enough sex hormones, which can affect your sex drive and fertility. It can happen when your anterior pituitary releases lower-than-normal levels of follicle-stimulating hormone (FSH) and/or luteinizing hormone (LH), leading in turn to low levels of testosterone and estrogen.

Hypothyroidism: If your anterior pituitary releases too little thyroid-stimulating hormone (TSH), it can cause hypothyroidism, which is when your thyroid gland is underactive and releases too little of its own hormones.

Hyperpituitarism conditions

Conditions that are the result of higher-than-normal levels of one or more anterior pituitary hormones include:

Acromegaly: Acromegaly is a very rare condition that happens when a benign (noncancerous) tumor in your anterior pituitary produces too much growth hormone (GH). It affects your body's bones and tissues and causes them to grow in abnormal ways. Acromegaly affects adults, and common symptoms include an increase in size of your hands, feet, lips and jaw.

Cushing's disease: Cushing's syndrome happens when your adrenal glands make too much cortisol. Cushing's disease, a type of Cushing's syndrome, happens when your adrenal glands are making too much cortisol because of a problem in your anterior pituitary. Cushing's disease is caused by a benign tumor in your anterior pituitary that makes excess adrenocorticotrophic hormone (ACTH), which causes your adrenal glands to make too much cortisol. It can cause rapid weight gain, mainly in your face, abdomen and the back of your neck, as well as other symptoms.

Hyperthyroidism: If your anterior pituitary releases too much thyroid-stimulating hormone (TSH), usually from a benign pituitary tumor, it can cause hyperthyroidism, which is when your thyroid gland is overactive and releases too much of its own hormones. This is a very rare cause of hyperthyroidism.

Pituitary gland tumors (adenomas)

A pituitary adenoma is a growth or tumor on your pituitary gland. Most pituitary adenomas are slow-growing and benign (noncancerous). Adenomas can put pressure on normal pituitary cells and keep them from working properly, leading to hypopituitarism, especially when they are large. They can also release extra pituitary hormones, leading to hyperpituitarism (pituitary hormone excess).

Pituitary adenomas make up 10% to 15% of all tumors that develop within the skull. They are found in about 77 out of 100,000 people, although researchers believe that they actually occur in as many as 20% of people at some point in their lives. However, many pituitary adenomas, especially very small ones, don't cause serious symptoms and are never discovered.

What tests can check the health of my anterior pituitary?

If you're experiencing symptoms related to anterior pituitary issues, your healthcare provider may order tests to check one or more of your anterior pituitary hormone levels, depending on what your symptoms are. These tests are usually blood tests.

If your test results come back abnormal, your provider may suggest undergoing an imaging test such as an MRI (magnetic resonance imaging) to take a look at your pituitary gland.
A note from Cleveland Clinic
Since your anterior pituitary is responsible for several different hormones that affect many aspects of your body and health, it can be difficult to pinpoint if certain symptoms are a result of issues with your anterior pituitary. If you're ever experiencing new or concerning symptoms, it's important to talk to your healthcare provider. They can usually run some simple tests to assess your health.

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Anterior Pituitary: What It Is & Function

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The anterior pituitary is the front lobe of your pituitary gland, which is a small, pea-sized gland located at the base of your brain below your hypothalamus.

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What are the common conditions and disorders that affect the posterior pituitary?

The main issues related to the posterior pituitary are hypersecretion (too much) of oxytocin or antidiuretic hormone (ADH, or vasopressin) and hyposecretion (too little) of oxytocin or ADH.

Most of these conditions are rare. Tumors can also affect your posterior pituitary, but they are also rare. Pituitary tumors more commonly affect the anterior lobe of your pituitary gland.

Hyposecretion of antidiuretic hormone (ADH, or vasopressin)

Hyposecretion of antidiuretic hormone (ADH, or vasopressin) happens when there's a decrease in either the production of ADH in your hypothalamus or the release of ADH from your pituitary gland. It's usually caused by damage to your hypothalamus or posterior pituitary and, in rare cases, by a gene mutation (change). In some cases, the cause is unknown.

Having lower-than-normal amounts of ADH prevents your kidneys from reabsorbing water, so it's released in your urine. This makes your urine very diluted (watery) and your blood very concentrated.

A lack of ADH can cause a rare water metabolism disorder called central diabetes insipidus (CDI). It's not to be confused with - and is not related to - diabetes mellitus, which happens when your body doesn't produce or properly use insulin. CDI can become life-threatening if it's not treated.

Symptoms and side effects of diabetes insipidus include:

Frequent urination (polyuria).

Extreme thirst (polydipsia).

Fatigue (due to having to wake up several times overnight to pee).

Dehydration.

Hypersecretion of antidiuretic hormone (ADH, or vasopressin)

Hypersecretion of antidiuretic hormone (ADH, or vasopressin) happens when there's an increase in either the production of ADH in your hypothalamus or the release of ADH from your posterior pituitary. When this happens, it's called the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Having excess amounts of ADH causes your body to retain too much water. This makes your urine very concentrated and your blood overly saturated with water (diluted).

There are several causes of SIADH and excess ADH levels. Some more common causes include:

Certain medications, such as certain Type 2 diabetes medications and anti-seizure medications.

Having surgery under general anesthesia.

Brain conditions, such as injury, infections and stroke.

Brain surgery in the region of your hypothalamus.

Symptoms of excess ADH levels are most often caused by having low sodium levels in your blood. Symptoms of having a low blood sodium level include:

Nausea and vomiting.

Problems with balance that may result in falls

Mental changes, such as confusion and memory problems.

Hyposecretion of oxytocin

Hyposecretion (too little secretion) of oxytocin is rare. Having lower-than-normal levels of oxytocin stop uterine contractions and milk ejection during the birthing process. Although it's rare, the most common cause of lower-than-normal oxytocin levels is a condition called panhypopituitarism, a condition in which all pituitary gland hormone levels are below normal.

Hypersecretion of oxytocin

Hypersecretion (too much secretion) of oxytocin is very rare and is called oxytocin toxicity. Higher-than-normal levels of oxytocin result in an overactive uterus, causing an increase in uterine muscle mass (hypertrophy), which limits pregnancy due to there not being enough space in the uterus to hold the fetus.

Are there tests that can check the health of my posterior pituitary?

If you're experiencing symptoms related to posterior thyroid issues, your healthcare provider may order tests to check your levels of antidiuretic hormone (ADH, or vasopressin) and/or oxytocin.

An antidiuretic hormone (ADH) blood test can help detect, diagnose and determine the cause of ADH deficiency and excess.

Your levels of oxytocin can be tested with several different fluids, including spit (saliva), blood, plasma, urine and cerebrospinal fluid.

If your test results come back abnormal, your provider may suggest having an imaging test such as an MRI (magnetic resonance imaging) to take a look at your pituitary gland.

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Posterior Pituitary: What It Is & Function

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The posterior pituitary is the back lobe of your pituitary gland, which is a small, pea-sized gland located at the base of your brain below your hypothalamus.

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Alternative names for growth hormone

Somatotropin; GH; human growth hormone; HGH

What is growth hormone?

Growth hormone is released into the bloodstream from the anterior pituitary gland. The pituitary gland also produces other hormones that have different functions from growth hormone.

Growth hormone acts on many parts of the body to promote growth in children. Once the growth plates in the bones (epiphyses) have fused growth hormone does not increase height. In adults, it does not cause growth but it helps to maintain normal body structure and metabolism, including helping to keep blood glucose levels within set levels.

How is growth hormone controlled?

Growth hormone release is not continuous; it is released in a number of 'bursts' or pulses every three to five hours. This release is controlled by two other hormones that are released from the hypothalamus (a part of the brain): growth hormone-releasing hormone, which stimulates the pituitary to release growth hormone, and somatostatin, which inhibits that release.

Growth hormone levels are increased by sleep, stress, exercise and low glucose levels in the blood. They also increase around the time of puberty. Growth hormone release is lowered in pregnancy and if the brain senses high levels of growth hormone or insulin-like growth factors already in the blood.

What happens if I have too much growth hormone?

Not surprisingly, too much growth hormone causes too much growth.

In adults, excessive growth hormone for a long period of time produces a condition known as acromegaly, in which patients have swelling of the hands and feet and altered facial features. These patients also have organ enlargement and serious functional disorders such as high blood pressure, diabetes and heart disease. Over 99% of cases are due to benign tumours of the pituitary gland, which produce growth hormone. This condition is more common after middle-age when growth is complete so affected individuals do not get any taller.

Very rarely, increased growth hormone levels can occur in children before they reach their final height, which can lead to excessive growth of long bones, resulting in the child being abnormally tall. This is commonly known as gigantism (a very large increase in height).

Overproduction of growth hormone is diagnosed by giving a sugary drink and measuring the growth hormone level over the next few hours. The sugar should cause growth hormone production to reduce. However, this does not happen in acromegaly.

What happens if I have too little growth hormone?

Too little growth hormone (deficiency) results in poor growth in children. In adults, it causes a reduced sense of wellbeing, increased fat, increased risk of heart disease and weak heart, muscles and bones. The condition may be present from birth where the cause can be unknown, genetic or due to injury to the pituitary gland (during development or at birth).

Growth hormone deficiency may also develop in adults due to brain injury, a pituitary tumour or damage to the pituitary gland (for example, after brain surgery or radiotherapy for cancer treatment). The main treatment is to replace the growth hormone using injections - either once a day or several times a week.

In the past, growth hormone treatment was stopped at the end of growth. It is now clear that growth hormone contributes to both bone mass and muscle mass reaching the best possible level, as well as reducing fat mass during development to an adult. The specialist is therefore likely to discuss the benefits of continuing growth hormone after growth has completed until age 25 to make sure bone and muscle mass reach the best possible level. Additionally, growth hormone has been linked to a sensation of wellbeing, specifically energy levels. There is evidence that 30-50% of adults with growth hormone deficiency feel tired to a level that impairs their wellbeing. These adults may benefit from lifelong treatment with growth hormone. Taking growth hormone when adult will not result in increased height.

Last reviewed: Feb 2018

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Somatotropin; GH; human growth hormone; HGH Growth hormone is released into the bloodstream from the anterior pituitary gland. The pituitary gland also produces other hormones that have different functions from growth hormone. Growth hormone acts on many parts of the body to promote growth in children.

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What is adrenocorticotropic hormone (ACTH)?

Adrenocorticotropic hormone (ACTH) is a hormone your pituitary gland releases that plays a large role in how your body responds to stress. The release of ACTH triggers your adrenal glands to produce cortisol, the "stress hormone," and androgens (a group of sex hormones).

Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues. These signals tell your body what to do and when to do it.

Your pituitary gland is a small, pea-sized gland located at the base of your brain below your hypothalamus. It's a part of your endocrine system. Your pituitary gland is made of two lobes: the anterior (front) lobe and posterior (back) lobe. Your anterior pituitary lobe makes and releases ACTH.

What is the function of adrenocorticotropic hormone (ACTH)?

The main function of adrenocorticotropic hormone is to stimulate your adrenal glands to release cortisol.

Cortisol is an essential hormone that affects almost every organ and tissue in your body. Cortisol is widely known as the "stress hormone." However, it has many important effects and functions throughout your body aside from regulating your body's stress response.

Cortisol's many important roles include:

Regulating your body's stress response.

Helping control your body's use of fats, proteins and carbohydrates, or your metabolism.

Suppressing inflammation.

Regulating blood pressure.

Regulating blood sugar.

Helping control your sleep-wake cycle.

ACTH also plays a role in stimulating your adrenal glands to release androgens (sex hormones) and stimulating the production of chemical substances that stimulate an increase in other hormones such as adrenaline and noradrenaline.

How are ACTH levels controlled?

Your body controls adrenocorticotropic hormone levels in a feedback system that involves your hypothalamus, pituitary gland, adrenal glands and certain hormones. This is called the hypothalamic-pituitary-adrenal (HPA) axis.

Your pituitary gland is connected to your hypothalamus through a stalk of blood vessels and nerves. This is called the pituitary stalk. Through the stalk, your hypothalamus communicates with your pituitary gland and tells it to release certain hormones. Your hypothalamus is the part of your brain that controls functions like blood pressure, heart rate, body temperature and digestion.

Your adrenal glands are small, triangle-shaped glands that are located on top of each of your two kidneys.

The feedback system that controls ACTH levels involves the following steps:

1. When cortisol levels are low, your hypothalamus releases corticotrophin-releasing hormone (CRH).

2. CRH stimulates your anterior pituitary lobe to release ACTH.

3. ACTH then triggers your adrenal glands, specifically your adrenal cortex, to release cortisol and androgens.

4. The resulting increase in cortisol then signals your hypothalamus to decrease CRH levels, thus completing the feedback loop.

Stress also stimulates adrenocorticotropic hormone production and the resulting increase in cortisol levels.

If there are any issues with your hypothalamus, pituitary gland or adrenal glands, it can affect the balance of hormones involved in this process, including ACTH.

What test checks ACTH levels?

A blood test can measure adrenocorticotropic hormone levels through a blood sample taken from a vein in your arm.

Healthcare providers often order an ACTH test along with a cortisol test to diagnose issues with your pituitary or adrenal glands.

Healthcare providers may also order an ACTH stimulation test, which measures how well your adrenal glands respond to ACTH, to help diagnose pituitary and/or adrenal gland issues.

What are normal ACTH levels?

Like cortisol, the level of ACTH in your blood normally peaks in the early morning and declines throughout the day, reaching its lowest level around midnight. This pattern can change if you work a night shift and sleep at different times of the day.

Because of this, ACTH tests usually require a morning blood draw. In general, the normal range for ACTH levels is 7.2 to 63.3 picograms per milliliter (pg/mL) from 7:00 a.m. to 10:00 a.m.

Normal ranges can vary from lab to lab, time to time and person to person. If you need to get an ACTH test, your healthcare provider will interpret your results and let you know if you need to get further testing.

What happens when ACTH levels are high?

If you have high levels of adrenocorticotropic hormone, you'll likely also have high cortisol levels. Since cortisol affects your body in many ways, you'll experience side effects of high cortisol levels, not necessarily high ACTH levels. In cases where your adrenal glands don't produce enough cortisol, you may have increased ACTH levels. Again, you'll experience symptoms related to low cortisol, not high ACTH.

Causes of high adrenocorticotropic hormone levels include:

Cushing's disease: This is the most common cause of increased ACTH levels. A benign (non-cancerous) tumor (adenoma) in your pituitary gland that produces excess amounts of ACTH, which then elevates cortisol levels, causes ACTH. It's important to note the difference between Cushing's disease and Cushing's syndrome. The disease is one of the many causes of the syndrome.

Ectopic adrenocorticotropic hormone tumor: Rarely, a tumor outside of your pituitary gland can release excess ACTH. Tumors that can (but rarely) produce ACTH include benign carcinoid tumors of the lung, islet cell tumors of the pancreas, medullary carcinoma of the thyroid, small cell tumors of the lung and tumors of the thymus gland.

Primary adrenal insufficiency: This condition happens when your adrenal glands don't produce enough cortisol due to some type of damage to your adrenal glands. Addison's disease is the most common cause of primary adrenal insufficiency. As a result, your pituitary gland releases excess ACTH to try to stimulate your adrenal glands.

What happens when ACTH levels are low?

Low adrenocorticotropic hormone levels due to a pituitary gland condition usually cause low cortisol levels, whereas high cortisol levels due to an adrenal gland issue usually cause low ACTH levels.

Causes of low ACTH levels include:

Cushing's syndrome: Cushing's syndrome from an adrenal tumor or by long-term use of corticosteroid medication for other conditions can cause low ACTH levels. This is because the excess cortisol prevents your pituitary gland from releasing regular amounts of ACTH.

Hypopituitarism: This is a rare condition in which there's a lack (deficiency) of one, multiple or all of the hormones made by your pituitary gland. ACTH can be one of the affected hormones. Any type of damage to your pituitary gland, such as pressure on the gland, surgical damage or radiation therapy, can cause hypopituitarism.

A note from Cleveland Clinic
Adrenocorticotropic hormone (ACTH) is essential for regulating your cortisol levels. If you're experiencing symptoms of high or low cortisol levels, such as weight gain or loss and high or low blood pressure, respectively, it's important to contact your healthcare provider. They may order cortisol and ACTH blood tests to see if your adrenal glands or pituitary gland are responsible for your symptoms.

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Adrenocorticotropic Hormone (ACTH): What It Is & Function

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Adrenocorticotropic hormone (ACTH) is a hormone your pituitary gland releases that triggers your adrenal glands to release cortisol, the "stress hormone."

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Alternative names for luteinising hormone

Interstitial cell stimulating hormone; luteinizing hormone; lutropin; LH

What is luteinising hormone?

Luteinising hormone, like follicle stimulating hormone, is a gonadotrophic hormone produced and released by cells in the anterior pituitary gland. It is crucial in regulating the function of the testes in men and ovaries in women.

In men, luteinising hormone stimulates Leydig cells in the testes to produce testosterone, which acts locally to support sperm production. Testosterone also exerts effects all around the body to generate male characteristics such as increased muscle mass, enlargement of the larynx to generate a deep voice, and the growth of facial and body hair.

In women, luteinising hormone carries out different roles in the two halves of the menstrual cycle. In weeks one to two of the cycle, luteinising hormone is required to stimulate the ovarian follicles in the ovary to produce the female sex hormone, oestradiol. Around day 14 of the cycle, a surge in luteinising hormone levels causes the ovarian follicle to tear and release a mature oocyte (egg) from the ovary, a process called ovulation. For the remainder of the cycle (weeks three to four), the remnants of the ovarian follicle form a corpus luteum. Luteinising hormone stimulates the corpus luteum to produce progesterone, which is required to support the early stages of pregnancy, if fertilisation occurs.

How is luteinising hormone controlled?

The secretion of luteinising hormone from the anterior pituitary gland is regulated through a system called the hypothalamic-pituitary-gonadal axis. Gonadotrophin-releasing hormone is released from the hypothalamus and binds to receptors in the anterior pituitary gland to stimulate both the synthesis and release of luteinising hormone (and follicle stimulating hormone). The released luteinising hormone is carried in the bloodstream where it binds to receptors in the testes and ovaries to regulate their hormone secretions and the production of sperm or eggs.

The release of hormones from the gonads can suppress the secretion of gonadotrophin-releasing hormone and, in turn, luteinising hormone from the anterior pituitary gland. When levels of hormones from the gonads fall, the reverse happens and gonadtrophin-releasing hormone and hence luteinising hormone rise. This is known as negative feedback.

In men, testosterone exerts this negative feedback and in women oestrogen and progesterone exert the same effect except at the midpoint in the menstrual cycle. At this point, high oestrogen secretions from the ovary stimulate a surge of luteinising hormone from the pituitary gland, which triggers ovulation.

The fine tuning of luteinising hormone release is vital to maintaining fertility. Because of this, compounds designed to mimic the actions of gonadotrophin-releasing hormone, luteinising hormone and follicle stimulating hormone are used to stimulate gonadal function in assisted conception techniques such as in vitro fertilisation ( IVF). Measuring the levels of luteinising hormone present in urine can be used to predict the timing of the luteinising hormone surge in women, and hence ovulation. This is one of the methods employed in ovulation prediction kits used by couples wishing to conceive.

What happens if I have too much luteinising hormone?

Too much luteinising hormone can be an indication of infertility. Since the secretion of luteinising hormone is tightly controlled by the hypothalamic-pituitary-gonadal axis, high levels of luteinising hormone in the bloodstream can indicate decreased sex steroid production from the testes or ovaries (for example, as in premature ovarian failure).

Polycystic ovary syndrome is a common condition in women associated with high levels of luteinising hormone and reduced fertility. In this condition, an imbalance between luteinising hormone and follicle stimulating hormone can stimulate inappropriate production of testosterone.

Genetic conditions, such as Klinefelter's syndrome and Turner syndrome, can also result in high luteinising hormone levels. Klinefelter's syndrome is a male-only disorder and results from carrying an extra X chromosome (so that men have XXY, rather than XY chromosomes). As a result of this, the testes are small and do not secrete adequate levels of testosterone to support sperm production. Turner syndrome is a female-only disorder caused by a partial or full deletion of an X chromosome (so that women have XO, rather than XX). In affected patients, ovarian function is impaired and therefore luteinising hormone production increases to try to stimulate ovarian function.

What happens if I have too little luteinising hormone?

Too little luteinising hormone will also result in infertility in both men and women, as a critical level of luteinising hormone is required to support testicular or ovarian function.

In men, an example of a condition where low levels of luteinising hormone are found is Kallmann's syndrome, which is associated with a deficiency in gonadotrophin-releasing hormone secretion from the hypothalamus.

In women, a lack of luteinising hormone means that ovulation does not occur and menstrual periods may not occur regularly. An example of a condition which can be caused by too little luteinising hormone is amenorrhoea.

Last reviewed: Feb 2018

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Luteinising hormone | You and Your Hormones from the Society for Endocrinology

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Luteinising hormone is produced by the pituitary gland and is one of the main hormones that control the reproductive system.

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TSH; thyrotropin, thyrotrophin Thyroid stimulating hormone is produced and released into the bloodstream by the pituitary gland. It controls production of the thyroid hormones, thyroxine and triiodothyronine, by the thyroid gland by binding to receptors located on cells in the thyroid gland.

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What is #LH? What Affects Luteinizing Hormone Levels and How you can #Check LH Levels

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What are the common conditions and disorders associated with luteinizing hormone?

LH levels fluctuate, especially with your menstrual cycle. A high or low LH level isn't simply good or bad.

For instance, a surge in your LH can show that you're about to ovulate. You're most likely to become pregnant at this time. This information that LH provides about your fertility is helpful if you're trying to have a baby.

LH levels in your body can signal problems, too. Knowing your LH level at a particular moment in time can help your provider learn:

If you have a pituitary disorder.

What's causing fertility issues.

What's causing you to have irregular periods (DFAB people).

How close you are to perimenopause or menopause (DFAB people).

What's causing you to have low testosterone levels (DMAB people).

LH levels tests can also help your provider diagnose early or delayed puberty in children.

What happens when luteinizing hormone levels are high?

High LH levels can signify that your sex organs aren't producing enough steroid hormones needed for a reproductive process to take place. This is typical of when the ovaries and testes have exhausted their ability to produce estrogen and testosterone, from genetic, autoimmune, surgical, or physiologic causes.

Turner syndrome or Fragile X in DFAB people and Klinefelter syndrome in DMAB people are examples of genetic conditions associated with high LH levels.

Polycystic ovary syndrome (PCOS) is a condition that affects DFAB people that can cause mildly elevated LH levels. These are associated with irregular periods and infertility.

What happens when luteinizing hormone levels are low?

Low LH levels can signify that your pituitary gland isn't making the LH needed to spur changes in your body that support sexual development or reproduction.

Low LH levels can be a sign of:

Kallmann syndrome: A rare condition that leads to insufficient testosterone and estrogen production.

Functional Hypothalamic Amenorrhea: When irregular or missed periods are related to excessive exercise habits.

Common tests to check luteinizing hormone levels?

An LH level test checks how much LH is in your blood and involves a simple blood draw. Sometimes, your healthcare provider will recommend doing an LH level test alongside an FSH test since these hormones work together to regulate your reproductive system.

What is a normal luteinizing hormone level?

When you get your test results, remember that what's considered normal depends on various factors, including your age, gender and medical history. For DFAB people, the timing of your menstrual cycle or whether you've gone through menopause will affect your LH levels.

The numbers below provide a general snapshot of normal LH levels for cisgender men and women. Ask your healthcare provider what your test results mean for you.

Women, weeks one and two of the menstrual cycle: 1.37 to 9 IU/L (international units per liter).

Women, week two, before ovulation: 6.17 to 17.2 IU/L.

Women, weeks three and four of the menstrual cycle: 1.09 to 9.2 IU/L.

Women, postmenopausal: 19.3 to 100.6IU/L.

Men: 1.42 to 15.4 IU/L.

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Luteinizing Hormone: Levels, Function & Testing

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Luteinizing hormone (LH) is a chemical in your body that stimulates important processes in your reproductive system, like ovulation.

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Alternative names for follicle stimulating hormone (FSH)

follitropin

What is follicle stimulating hormone?

Follicle stimulating hormone (or FSH) is one of the gonadotrophic hormones; the other being luteinising hormone (or LH). Both are released by the pituitary gland into the bloodstream. Follicle stimulating hormone is one of the hormones essential to pubertal development and the function of women's ovaries and men's testes. In women, this hormone stimulates the growth of ovarian follicles in the ovary before the release of an egg from one follicle at ovulation. It also increases oestradiol production from the ovaries. In men, follicle stimulating hormone acts on the Sertoli cells of the testes to stimulate sperm production (spermatogenesis).

How is follicle stimulating hormone controlled?

The production and release of follicle stimulating hormone is regulated by the levels of a number of circulating hormones released by the ovaries and testes. This system is called the hypothalamic-pituitary-gonadal (HPG) axis. Gonadotrophin-releasing hormone (GnRH) is released from the hypothalamus and binds to receptors in the anterior pituitary gland to stimulate both the synthesis and release of follicle stimulating hormone (FSH) and luteinising hormone (LH). As per the definition of a hormone, the released follicle stimulating hormone is carried by the bloodstream and binds to receptors in the testes and ovaries.

In women, when FSH levels fall towards the end of the menstrual cycle. This is sensed by the hypothalamus, which produces more gonadotrophin-releasing hormone (GnRH), which in turn stimulates the pituitary gland to produce more follicle stimulating hormone (FSH) and luteinising hormone (LH), and release these into the bloodstream. The rise in follicle stimulating hormone stimulates the growth of the follicle in the ovary.

As the follicles in the ovary grow, they produce increasing amounts of oestradiol and inhibin. In turn, these hormones act on the hypothalamus and pituitary gland to reduce the release of gonadotrophin-releasing hormone and follicle stimulating hormone (negative feedback). This causes a fall in FSH, which prevents too many follicles developing each cycle. The largest follicle is less dependent on FSH for its growth and is able to continue growing even if FSH levels fall. However, smaller follicles can no longer survive as FSH levels fall due to negative feedback, enabling the emergence of a single dominant follicle.

As this follicle grows, it produces more and more oestrogen, which stimulates a surge in luteinising hormone and follicle stimulating hormone (positive) from the pituitary gland. This rise in LH leads to the release of an egg from the follicle, termed 'ovulation'.

In summary, during each menstrual cycle, there is a rise in follicle stimulating hormone secretion in the first half of the cycle (follicular phase) that stimulates follicular growth in the ovary. After ovulation the ruptured follicle forms a corpus luteum that produces high levels of progesterone (luteal phase). Towards the end of the cycle the corpus luteum breaks down, progesterone production decreases and the next menstrual cycle begins as follicle stimulating hormone levels start to rise again.

In men, the production of follicle stimulating hormone is regulated by circulating levels of inhibin. If spermatogenesis is impaired, this will lead to less inhibin being produced by the testes. The usual action of inhibin is to inhibit FSH release from the pituitary gland. Thus, impaired spermatogenesis leads to less inhibin and thus an increase in FSH release from the pituitary gland.

Testosterone levels within the testes are also needed for spermatogenesis. This testosterone production within the testes is stimulated by the action of luteinising hormone. This 'negative feedback' control of testosterone on LH secretion and spermatogenesis on inhibin secretion ensures that the production of spermatogenesis and sex steroids remains steady. Excess testosterone in the body (for example after taking extra testosterone-like drugs in order to stimulate muscle growth) can result in low levels of FSH and LH and thus impair spermatogenesis.

What happens if I have too much follicle stimulating hormone?

Most often, raised levels of follicle stimulating hormone are a sign of malfunction in the ovary or testis. If the gonads fail to create enough oestrogen, testosterone and/or inhibin, due to loss of negative feedback on the pituitary gland, the levels of both follicle stimulating hormone and luteinising hormone will rise. This condition is called hypergonadotrophic- hypo gonadism, and is associated with primary ovarian insufficiency or testicular failure. This is seen in conditions such as Klinefelter's syndrome in men and Turner syndrome in women.

In women, follicle stimulating hormone levels also start to rise naturally in women in the lead up to menopause, reflecting a reduction in the function of the ovaries and decline of oestrogen and inhibin production.

There are very rare pituitary conditions that can raise the levels of follicle stimulating hormone in the bloodstream. This overwhelms the normal negative feedback loop and can (rarely) cause ovarian hyperstimulation syndrome in women. Symptoms of this include enlarging of the ovaries and a potentially dangerous accumulation of fluid in the abdomen (triggered by the rise in ovarian steroid output), which leads to pain in the pelvic area.

What happens if I have too little follicle stimulating hormone?

In women, a lack of follicle stimulating hormone leads to incomplete development at puberty and poor ovarian function (ovarian insufficiency). In this situation ovarian follicles do not grow properly and do not release an egg, thus leading to infertility. Since levels of follicle stimulating hormone in the bloodstream are low, this condition is called hypogonadotrophic hypo gonadism. This is seen in a condition called Kallman's syndrome, which is associated with a reduced sense of smell.

Sufficient follicle stimulating hormone action is also needed for full sperm production. In the case of complete absence of follicle stimulating hormone in men, lack of puberty and infertility due to lack of sperm (azoospermia) can occur. Partial follicle stimulating hormone deficiency in men can cause delayed puberty and limited sperm production (oligozoospermia), but fathering a child may still be possible. If the loss of follicle stimulating hormone occurs after puberty, there will be a similar loss of fertility.

Last reviewed: Mar 2021

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Follicle stimulating hormone is produced by the pituitary gland. It regulates the functions of both the ovaries and testes. Lack or low levels of it can cause subfertility in both men and women.

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What is FSH? Follicle-stimulating #Hormone and What Affects #FSH Levels Explained

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Antidiuretic Hormone (ADH) - Secretion and Functions

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Antidiuretic hormone (ADH) helps regulate the amount of water in your body. It works to control the amount of water your kidneys reabsorb as they filter out waste from your blood. This hormone is also called arginine vasopressin (AVP).

Determining Your ADH Levels

ADH testing alone won't diagnose your condition. However, your doctor may complete the test to distinguish between central diabetes insipidus, nephrogenic diabetes insipidus, and SIADH.

If your doctor suspects that your ADH levels are wrong, they may complete a water loading or water deprivation test. Keep in mind that ADH test results don't diagnose any health conditions. Your doctor assesses other symptoms and lab work along with your medical history and a physical exam. You may receive treatment for another health condition, like an infection, that will, in turn, improve symptoms of high or low ADH levels.‌

Water deprivation test. Do not attempt to self-diagnose at home. A water deprivation test should only be performed under medical supervision. Your doctor may instruct you to stop drinking fluids for a period of time. Once the time passes, the blood test is administered.

Your doctor may inject a synthetic ADH and take blood at certain intervals to monitor your body's response to restricted fluids alongside the additional ADH. Dehydration is possible, so talk to your doctor about any concerns you have before beginning the test.

Water loading test. Similar to the water deprivation test, this test must be performed under medical supervision. You'll need to fast for a certain amount of time ahead of the test.

Then, your doctor has you drink specific quantities of water. They monitor changes in your blood and urine throughout the procedure. With a water loading test, your doctor anticipates that you won't produce as much urine as you should.

Keep in mind that some medications impact your ADH levels. Talk to your doctor about any medications when you address your symptoms and concerns. Drugs and medications that impact your ADH levels include:

Barbiturates

Desipramine

Morphine

Nicotine

Amitriptyline

Carbamazepine

Acetaminophen

Metformin

Tolbutamide

Aspirin

Theophylline

Non-steroidal anti-inflammatory medications

Ethanol

Lithium‌

Phenytoin

Treating and Preventing ADH Symptoms

You may not be able to completely prevent your ADH levels from fluctuating over time, but you can maintain a healthy diet and drink plenty of water.

Treating ADH is possible. You can replace low levels of ADH by taking a synthetic form of the hormone in pill form. Your doctor may also suggest drinking more water and making changes to your diet and lifestyle.‌

If you take medications that impact your ADH levels, your doctor may ask you to consider alternative options. If you smoke or drink, you may need to cut back or stop altogether to see an improvement in your condition.

Understanding Antidiuretic Hormones

Your hypothalamus, an area at the base of your brain, produces ADH. Sensors in your body detect when your blood volume changes and needs more ADH. These sensors talk to your brain and the pituitary gland releases ADH into your bloodstream.

When ADH makes it to your kidneys, it signals them to conserve water and produce more concentrated urine. The water your body retains has effects on your body, including:

Diluting your blood

Lowering your blood's osmolality‌

Increasing your blood volume

‌Increasing your blood pressure

If this doesn't restore the balance of water in your body, your brain also signals thirst, so you're more likely to drink water. If this is not sufficient to restore the water balance, then thirst is also stimulated so that the affected person will drink more water.‌

Many health conditions affect the amount of ADH your body releases or the way your kidneys respond to it. You may have too much or too little ADH. If your body doesn't produce enough ADH or your kidneys don't respond to it, your body loses too much water in urine output. Signs of low ADH include:

Excessive thirst

Frequent urination

Dehydration‌

High blood sodium levels‌

If your body produces too much ADH and water is retained, your blood volume increases and leads to symptoms like:

Feeling nauseous

Headaches

Disorientation‌

Tired or lethargic feeling

‌Low blood sodium levels

There's a test for ADH levels in your blood, but medical professionals don't use it very often. Instead, an imbalance of ADH is diagnosed based on your medical history and other lab tests like urine, blood osmolality, and electrolytes.

If your body doesn't produce enough ADH, it's called diabetes insipidus and there are two types. Nephrogenic diabetes insipidus is characterized by your kidneys' inability to respond to ADH. It may be inherited, but is also a symptom of larger health conditions.

Central diabetes insipidus refers to the condition in which your pituitary gland doesn't produce enough ADH. It may be caused by:

Inherited genetic defect

Head trauma

Brain tumor‌

Infection

Too much ADH is a condition called the syndrome of inappropriate antidiuretic hormone (SIADH). If you have SIADH, ADH releases into your blood sporadically. Sometimes it releases the correct amount, and other times it releases far more than your body needs.

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What to Know About Antidiuretic Hormone (ADH)

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Antidiuretic hormone (ADH) helps regulate the amount of water in your body. It works to control the amount of water your kidneys reabsorb as they filter out waste from your blood. This hormone is also called arginine vasopressin (AVP). ADH testing alone won't diagnose your condition.

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Adrenocorticotropic Hormone (ACTH) | Adrenal Gland

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What is prolactin?

Prolactin (also known as lactotropin and PRL) is a hormone that's responsible for lactation, certain breast tissue development and contributes to hundreds of other bodily processes. Prolactin levels are normally low in people assigned male at birth (AMAB) and non-lactating and non-pregnant people. They're normally elevated in people who are pregnant or breastfeeding (chestfeeding).

Most of your prolactin comes from your pituitary gland. It makes and releases (secretes) the hormone.

Your pituitary gland is a small, pea-sized gland located at the base of your brain below your hypothalamus. It's a part of your endocrine system and is in charge of making many different important hormones, including prolactin. Dopamine (a brain chemical) and estrogen (a hormone) control prolactin production and release from your pituitary gland.

Your central nervous system, immune system, uterus and mammary glands are also capable of producing prolactin. The following factors can contribute to prolactin creation in these tissues:

How does prolactin affect my body?

Prolactin contributes to hundreds of bodily functions, but its two main functions include:

The development of mammary glands within breast tissues and milk production.

Lactation and breastfeeding (chestfeeding).

Prolactin's role in mammary gland development and milk production

During pregnancy, the hormones prolactin, estrogen and progesterone stimulate breast tissue development and milk production.

Prolactin promotes the growth of a certain type of breast tissue called mammary alveoli, which are the components of the mammary gland where the production of milk occurs. Prolactin also stimulates the breast alveolar cells to create milk components, including:

Lactose (the carbohydrate component of milk).

Casein (the protein component of milk).

Lipids (components that provide energy, essential fatty acids and cholesterol).

Prolactin's role in lactation and breastfeeding (chestfeeding)

After delivery of your baby, progesterone levels drop, which increases the number of prolactin receptors on the mammary alveolar cells. This allows for milk secretion through your nipple, commonly known as lactation.

After delivery, prolactin levels don't remain constantly elevated. Prolactin levels will only spike during periods of nipple stimulation through suckling by your baby. As long as your baby maintains suckling, prolactin levels stay elevated. During periods when you're not breastfeeding, your prolactin levels decrease, and milk production reduces. If a person doesn't breastfeed their baby, prolactin levels fall to non-pregnant levels after one to two weeks.

What causes prolactin to increase?

Prolactin levels normally rise during pregnancy and breastfeeding (chestfeeding). They may also rise slightly due to the following situations:

Physical stress, such as experiencing pain.

Exercise.

Eating a meal.

Sexual intercourse.

Nipple stimulation unrelated to chestfeeding.

Injury to your chest area.

Epileptic seizures.

These increases in prolactin are usually slight and temporary. Certain conditions and medications can cause long-term (persistent) elevated prolactin levels.

What test measures prolactin levels?

A prolactin (PRL) test measures the level of prolactin in your blood. Your healthcare provider may order a prolactin blood test for you if you experience signs and symptoms of elevated prolactin levels and/or to evaluate the function of your pituitary gland.

What are normal prolactin levels?

Normal value ranges for prolactin levels may vary slightly among different laboratories. Be sure to look at the range of normal values listed on your laboratory report or ask your healthcare provider if you have questions about your results.

In general, the normal values for prolactin include:

For people assigned male at birth: Less than 20 ng/mL (nanograms per milliliter).

For people assigned female at birth who are not pregnant or chestfeeding: less than 25 ng/mL.

For people who are pregnant or chestfeeding: 80 to 400 ng/mL.

What are the signs and symptoms of high prolactin levels?

For anyone, higher-than-normal prolactin levels in your blood can cause the following symptoms:

Infertility.

Loss of interest in sex.

Milky discharge from your nipples when not pregnant or chestfeeding (galactorrhea).

For people assigned female at birth (AFAB), symptoms of excess prolactin include:

Changes in menstruation not related to menopause, such as irregular periods (menstruation) or no periods (amenorrhea).

Pain or discomfort during penetrative sex due to vaginal dryness.

For people assigned male at birth (AMAB), common symptoms of a prolactinoma include:

What causes abnormally high levels of prolactin?

Several factors and conditions can cause higher-than-normal levels of prolactin in your blood ( hyperprolactinemia), including:

Prolactinoma, a pituitary gland tumor (most common cause).

Certain medications.

Certain health conditions.

Other pituitary gland tumors.

Prolactinomas can cause elevated prolactin levels

A prolactinoma is the most common cause of higher-than-normal prolactin levels in your blood. A prolactinoma is a benign (non-cancerous) tumor that forms in your pituitary gland and causes excess production of prolactin. It's a type of pituitary adenoma.

Prolactinomas occur most commonly in people under the age of 40. They're more common in people assigned female at birth (AFAB) than in people assigned male at birth (AMAB). They rarely occur in children and adolescents.

Healthcare providers usually treat prolactinomas with medication, but they can also be treated with surgery and radiation therapy.

Medications that can cause elevated prolactin levels

The brain chemical dopamine helps suppress the production of prolactin in your body. Any medication that affects the production or use of dopamine in your body can make your prolactin levels rise.

Medications that can increase prolactin levels include:

Certain antipsychotic medications, such as risperidone.

Certain high blood pressure medications.

Medications that treat nausea and vomiting.

Pain relievers that contain opioids.

If you have high prolactin levels due to a medication, your levels will usually return to normal three to four days after you stop taking the medication. Never stop taking a prescribed medication unless your healthcare provider has told you to do so.

Health conditions that can cause elevated prolactin levels

Health conditions other than a prolactinoma that may cause hyperprolactinemia include:

Kidney disease.

Hypothyroidism (underactive thyroid).

Shingles, especially if the rash or blisters are on your chest.

Other pituitary gland tumors that can cause elevated prolactin levels

Large tumors (other than prolactinomas) located in or near your pituitary gland can cause hyperprolactinemia by reducing the effect of dopamine. Prolactin release is suppressed by dopamine, but if the tumor blocks the flow of dopamine to the prolactin-producing cells, then hyperprolactinemia will develop.

What causes abnormally low levels of prolactin?

Your prolactin levels are usually low unless you're pregnant or breastfeeding (chestfeeding), so the only sign of having lower-than-normal levels of prolactin is a lack of breastmilk production after giving birth.

In these cases, hypopituitarism is often the cause. Hypopituitarism is a rare condition in which there's a lack (deficiency) of one, multiple or all of the hormones your pituitary gland makes. It's usually caused by abnormal pressure on your pituitary gland or damage to your pituitary gland.

When should I see my doctor about my prolactin levels?

If you experience symptoms of excess prolactin levels (hyperprolactinemia), such as irregular periods and/or loss of interest in sex, contact your healthcare provider. They can order a simple blood test to check your prolactin levels.
A note from Cleveland Clinic
Prolactin is an important hormone for pregnancy and chestfeeding. While having higher-than-normal prolactin levels if you're not pregnant or chestfeeding isn't life-threatening, it can cause certain issues, such as infertility, and lower your quality of life. Be sure to contact your healthcare provider if you're experiencing signs or symptoms of hyperprolactinemia. They're available to help you.

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Prolactin: What It Is, Function & Symptoms

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Prolactin is a hormone that's responsible for lactation, certain breast tissue development and milk production. Excess levels of prolactin can cause certain symptoms.

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Thyroid Stimulating Hormone | UCLA Endocrine Center

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Anterior v Posterior Pituitary Gland - PLUS Anterior Pituitary Hormones Mnemonic (FLAT PEG)

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Alternative names for oxytocin

Alpha-hypophamine; manufactured versions - syntocinon and pitocin (both synthetic oxytocin); carbetocin (an analogue of oxytocin with similar structure)

What is oxytocin?

Oxytocin is produced in the hypothalamus and is secreted into the bloodstream by the posterior pituitary gland. Secretion depends on electrical activity of in the hypothalamus - it is released into the blood when these cells are excited.

The two main actions of oxytocin in the body are contraction of the womb (uterus) during childbirth and . Oxytocin stimulates the uterine muscles to contract and also increases production of prostaglandins, which increase the contractions further. Manufactured oxytocin is sometimes given to induce if it has not started naturally or it can be used to strengthen contractions to aid childbirth. In addition, manufactured oxytocin is often given to speed up delivery of the and reduce the risk of heavy bleeding by contracting the uterus. During breastfeeding, oxytocin promotes the movement of milk through the ducts in the breast, allowing it to be excreted by the nipple. Oxytocin is also present in men, playing a role in sperm transport and production of testosterone by the .

In the brain, oxytocin acts as a chemical messenger and has an important role in many human behaviours

Oxytocin is a hormone that acts on organs in the body (including the breast and uterus) and as a chemical messenger in the brain, controlling key aspects of the reproductive system, including childbirth and lactation, and aspects of human behaviour.

Alternative names for oxytocin

Alpha-hypophamine; manufactured versions - syntocinon and pitocin (both synthetic oxytocin); carbetocin (an analogue of oxytocin with similar structure)

What is oxytocin?

Oxytocin is produced in the hypothalamus and is secreted into the bloodstream by the posterior pituitary gland. Secretion depends on electrical activity of in the hypothalamus - it is released into the blood when these cells are excited.

The two main actions of oxytocin in the body are contraction of the womb (uterus) during childbirth and . Oxytocin stimulates the uterine muscles to contract and also increases production of prostaglandins, which increase the contractions further. Manufactured oxytocin is sometimes given to induce if it has not started naturally or it can be used to strengthen contractions to aid childbirth. In addition, manufactured oxytocin is often given to speed up delivery of the and reduce the risk of heavy bleeding by contracting the uterus. During breastfeeding, oxytocin promotes the movement of milk through the ducts in the breast, allowing it to be excreted by the nipple. Oxytocin is also present in men, playing a role in sperm transport and production of testosterone by the .

In the brain, oxytocin acts as a chemical messenger and has an important role in many human behaviours including sexual arousal, recognition, trust, romantic attachment and mother-infant bonding. As a result, oxytocin has been called the 'love hormone' or 'cuddle chemical'.

The effect of oxytocin on the brain is complex. Current research is focused on examining the role of oxytocin in various disorders including addiction, depression, post-traumatic stress, anxiety and anorexia.

How is oxytocin controlled?

Oxytocin production and secretion is controlled by a positive feedback mechanism where release of the hormone causes an action that stimulates more of its own release. For example, when contraction of the uterus starts during childbirth, oxytocin is released. This stimulates more contractions and more oxytocin to be released. In this way, contractions increase in intensity and frequency.

There is also a positive feedback involved in the milk-ejection reflex. Stimulation of the nipple during breastfeeding leads to increased oxytocin production and secretion into the blood, which then causes milk to be let down into the breast. The positive feedback cycle is maintained until the baby stops suckling. The production of oxytocin during childbirth is also self-limiting; release of the hormone is stopped once the baby is delivered.

What happens if I have too much oxytocin?

At present, the implications of having too much oxytocin are not clear. High levels have been linked to prostatic hyperplasia, a condition which affects the prostate in more than half of men over the age of 60. This may cause difficulty in passing urine.

It may be possible to treat this condition by manipulating oxytocin levels; however, more research is needed before any possible treatments are available.

What happens if I have too little oxytocin?

Similarly, it is not fully understood at present if there are any implications of having too little oxytocin in the body. A lack of oxytocin in a nursing mother would prevent the milk-ejection reflex and prevent breastfeeding.

Low oxytocin levels have been linked to autism and autistic spectrum disorders (e.g. Asperger syndrome) - a key element of these disorders being poor social functioning. Some scientists believe oxytocin could be used to treat these disorders. In addition, low oxytocin has been linked to depressive symptoms and it has been proposed as a treatment for depressive disorders. However, there is not enough evidence at present to support its use for any of these conditions.

Last reviewed: Dec 2020

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Oxytocin is a hormone that acts on organs in the body (including the breast and uterus) and as a chemical messenger in the brain, controlling key aspects of the reproductive system, including childbirth and lactation, and aspects of human behaviour.

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Oxytocin: What It Is, Function & Effects

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Oxytocin is a natural hormone that stimulates uterine contractions in childbirth and lactation after childbirth. It also affects aspects of human behavior.

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What is human growth hormone (HGH)?

Human growth hormone, also known as HGH and somatotropin, is a natural hormone your pituitary gland makes and releases that acts on many parts of the body to promote growth in children. Once the growth plates in your bones (epiphyses) have fused, HGH no longer increases height, but your body still needs HGH. After you've finished growing, HGH helps to maintain normal body structure and metabolism, including helping to keep your blood sugar (glucose) levels within a healthy range.

Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, muscles and other tissues. These signals tell your body what to do and when to do it. Your body makes over 50 hormones, and many of them interact with each other, creating a complex web of processes.

Your pituitary gland is a small, pea-sized endocrine gland located at the base of your brain below your hypothalamus. It's made of two lobes: the anterior (front) lobe and posterior (back) lobe. Your anterior lobe makes HGH.

Your pituitary gland is connected to your hypothalamus through a stalk of blood vessels and nerves. This is called the pituitary stalk. Your hypothalamus is the part of your brain that controls functions like blood pressure, heart rate, body temperature and digestion. Through the stalk, your hypothalamus communicates with your pituitary gland and tells it to release certain hormones. In this case, your hypothalamus releases growth hormone-releasing hormone (GHRH), which stimulates your pituitary gland to release HGH, and somatostatin, which prevents (inhibits) that release.

Healthcare providers use a synthetic form of HGH (sometimes called recombinant HGH) to treat certain health conditions, including growth hormone deficiency. You should never take synthetic HGH without a prescription from your provider.

What triggers human growth hormone (HGH)?

Your pituitary gland normally releases HGH in short bursts (pulses) throughout the day. The release of HGH is mainly controlled by two hormones your hypothalamus releases: growth hormone-releasing hormone (GHRH), which stimulates hGH release, and somatostatin, which prevents (inhibits) HGH release.

Several other endocrine hormones also regulate HGH, including insulin-like growth factor 1 (IGF-1). IGF-1 is a major suppressor of GH production, whereas thyroxine, glucocorticoids and ghrelin stimulate HGH release.

IGF-1 that's released by your liver is one of the best-characterized effects of HGH activity. IGF-1 plays a critical role in preventing (inhibiting) the release of the HGH through a negative feedback loop by stimulating somatostatin and inhibiting GHRH release. However, HGH and IGF-1 secretion are regulated by each other, where HGH triggers IGF-1 release and the IGF-1 inhibits HGH release in a feedback loop. In healthy people, HGH release is inhibited by hyperglycemia (high blood sugar) and stimulated by sleep, stress, exercise, hypoglycemia (low blood sugar) and amino acids.

What is the function of human growth hormone (HGH)?

Human growth hormone has two main functions: stimulating growth (mainly in children) and impacting metabolism (how your body turns the food you eat into energy).

HGH and growth

Human growth hormone triggers growth in nearly every tissue and organ in your body. However, it's most well-known for its growth-promoting effect on cartilage and bone, especially in the adolescent years during puberty. Cells in cartilage called chondrocytes and cells in bones called osteoblasts receive signals from HGH to increase replication and thus allow for growth in size.

Once the growth plates in a child's bones have fused, HGH no longer increases height. Instead, HGH helps to maintain normal body structure throughout the rest of your life.

HGH and metabolism

Metabolism consists of the chemical reactions in your body that change the food you eat into energy. All of the cells in your body need energy to function properly. Several different complex processes are involved in metabolism.

HGH impacts metabolism primarily by increasing the production of insulin-like growth factor-1 (IGF-1) and its effect on cells in your body. IGF-1 is a hormone similar in structure to insulin that manages the effects of HGH in your body. Insulin is an essential hormone your pancreas makes that helps regulate your blood sugar (glucose) levels by decreasing them. Like insulin, IGF-1 has glucose-lowering effects.

Your body normally carefully regulates your blood glucose levels. Blood glucose, or sugar, is the main sugar found in your blood. You get glucose from carbohydrates in the food you eat. This sugar is an important source of energy and provides nutrients to your body's organs, muscles and nervous system.

Insulin is the main hormone your pancreas makes to lower blood glucose levels when they get too high, and glucagon is the main hormone your pancreas makes to raise glucose levels when they get too low. Other hormones can counteract the effects of insulin, such as epinephrine (adrenaline) and cortisol.

While HGH normally increases blood glucose levels when they get too low, if you have excess amounts of HGH in your body, it can counteract the effects of insulin, causing elevated blood glucose levels.

Can HGH make you taller?

Human growth hormone increases vertical growth in children. However, once your growth plates have fused, HGH cannot make you taller. Instead, after you've reached your final height, HGH helps maintain your body's structure and has other important effects on your metabolism.

What are normal levels of human growth hormone (HGH)?

Your pituitary gland releases HGH in pulses. The size and duration of the pulses vary with the time of day and your age and sex. Because of this, random HGH measurements are rarely useful to healthcare providers in confirming or ruling out a diagnosis. Instead, HGH measurement tests are most useful when measured as part of a stimulation or suppression test.

In general, the normal range for HGH levels include:

For adults assigned male at birth: 0.4 to 10 nanograms per milliliter (ng/mL), or 18 to 44 picomoles per liter (pmol/L).

For adults assigned female at birth: 1 to 14 ng/mL, or 44 to 616 pmol/L

For children: 10 to 50 ng/mL, or 440 to 2200 pmol/L

Normal value ranges may vary from lab to lab. Be sure to reference your lab's normal range on your lab report when analyzing your results. If you have any questions about your results, talk to your healthcare provider.

What happens when human growth hormone (HGH) levels are too low?

Having lower-than-normal levels of HGH is called growth hormone deficiency. It's usually due to an issue with or damage to your pituitary gland that results in hypopituitarism - when one, several or all of the hormones your pituitary gland makes are deficient. Human growth hormone could be one of the affected hormones.

Growth hormone deficiency affects adults and children differently.

HGH deficiency in adults

When adults have a lack of HGH, it causes the following issues:

Reduced sense of well-being.

Increased body fat.

Increased risk of heart disease.

Weak heart, muscles and bones.

In adults, hypopituitarism that results in HGH deficiency may develop due to a benign pituitary adenoma (a noncancerous tumor) or damage to your pituitary gland or hypothalamus.

HGH deficiency in children

A lack of HGH in children results in poor growth. The main sign of HGH deficiency in children is slow height growth each year after a child's third birthday. This means they grow less than about 1.4 inches in height a year. A child with HGH deficiency may also have:

A younger-looking face than what's expected for their age.

Impaired hair growth.

Delayed puberty.

In children, hypopituitarism that results in HGH deficiency may be present from birth where the cause can be unknown (idiopathic), genetic or due to injury to their pituitary gland (during fetal development or at birth).

Children can also develop hypopituitarism due to damage to their pituitary gland or hypothalamus later in life.

What happens when human growth hormone (HGH) levels are too high?

The main condition associated with higher-than-normal HGH levels is a condition called acromegaly, though it affects adults and children differently. It's a rare condition.

Acromegaly in adults

Adults with acromegaly usually have enlarged or swollen hands and feet and altered facial features.

Adults with acromegaly can also have thickened bones and enlarged organs and are more likely to have conditions such as high blood pressure (hypertension), Type 2 diabetes and heart disease. Over 99% of acromegaly cases are due to pituitary adenomas, noncancerous (benign) tumors on your pituitary gland. These tumors can produce excess amounts of HGH. Acromegaly is more common after middle-age when growth is complete. Because of this, adults with acromegaly don't get any taller. Instead, their bones can become thicker.

Acromegaly in children

Very rarely, children can experience elevated growth hormone levels before they reach their final height, which can lead to excessive growth of long bones and very tall height. This condition is called pediatric acromegaly, but it's sometimes called gigantism. If left untreated, children with acromegaly usually grow to be seven feet tall or taller. Children with acromegaly may also have general weakness, delayed puberty and headaches.

Pituitary adenomas are usually the cause of pediatric acromegaly.

What test measures HGH levels?

Your healthcare provider can order a series of blood tests to check your HGH levels if you're experiencing symptoms related to HGH issues.

Your pituitary gland normally releases HGH into your bloodstream in pulses throughout the day and night, with peaks that occur mostly during the night. Because of this, a single blood test to measure HGH measurement is difficult to interpret and is not usually medically useful.

Providers most often use procedures called growth hormone stimulation and suppression tests to diagnose conditions caused by HGH deficiency or excess.

They may also order a blood test that measures the amount of insulin-like growth factor 1 (IGF-1) in your blood.

How is HGH used as medication?

The U.S. Food and Drug Administration (FDA) has approved the synthetic form of HGH for the treatment of certain conditions. The synthetic form of HGH is available only by prescription and is injected.

In children, healthcare providers prescribe HGH to treat:

Growth hormone deficiency.

Conditions that cause short stature, such as chronic kidney disease, Turner syndrome and Prader-Willi syndrome.

In adults, providers prescribe HGH to treat:

Growth hormone deficiency.

Loss of muscle tissue from HIV.

Short bowel syndrome.

It's important to only take synthetic HGH if your provider has prescribed it for you.

What are the side effects of synthetic HGH?

The use of synthetic HGH for medical treatment can cause certain side effects including:

Carpal tunnel syndrome.

Increased insulin resistance and/or Type 2 diabetes.

Swelling in your arms and legs (edema).

Joint and muscle pain.

Enlargement of breast tissue (gynecomastia) in people assigned male at birth.

Increased risk of certain cancers.

Researchers don't have enough information about the long-term effects of HGH treatment.

When should I see my healthcare provider about my HGH levels?

If you or your child are experiencing symptoms related to HGH deficiency or excess, contact your healthcare provider.

If you're receiving treatment for abnormal HGH levels, it's important to see your provider regularly to make sure your treatment is working.
A note from Cleveland Clinic
Human growth hormone (HGH) is a powerful hormone that's necessary for several important bodily processes. Sometimes, your pituitary gland can make too much or too little of it. If you or your child are experiencing symptoms related to HGH deficiency or excess, it's important to talk to your healthcare provider. They're there to help.

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HGH (Human Growth Hormone): What It Is, Benefits & Side Effects

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Human growth hormone (HGH) is a natural hormone your pituitary gland releases that promotes growth, helps maintain normal body structure and affects metabolism.