# data[].attributes.body
They believed that the nitrogen in the rat's urine came from the proteins the rats eat. They also thought that the proteins in our body needed replacement when they get old.

# data[].attributes.headline
Where do proteins go when they are eaten?

# data[].attributes.subject
Where do proteins go when they are eaten?

# data[].attributes.body
isotope is a new tool that scientists can use to address how much protein that is eaten is excreted and how much becomes part of proteins in the body. leucine is in the experiment with amino acids because its very important dietary amino acids

# data[].attributes.body
Some proteins in the body need to be replaced because they get old and need to be new proteins. So, some of the proteins that rats eat help to make the new proteins. Some of the proteins in the urine have to come from the old proteins that have to be replaced.

# data[].attributes.body
The nitrogen isotope intake was accepted all over the body, while some areas, mainly the blood plasma, accepted it more than some, like the organs. Still, considering muscle and skin make up a large part of the body, they received a large amount of the nitrogen. Moreover, because all parts of the body showed signs of nitrogen isotope, they knew that the amino acids that the rats ate built up new proteins for the body.

# data[].attributes.body
Rats excrete some of the amino acids they eat in the form of urine, but the majority of these amino acids are converted into proteins, which serve as the building blocks for cells. That concludes that most of the amino acids that rats eat go through the chemical pathway that forms protein that is needed for energy.