Estimation of Protein Catabolism by Urinary Nitrogen Relies on the Fact

Question

Estimation of protein catabolism by urinary nitrogen relies on the fact that
A) Protein used for energy does not produce CO2
B) The main excretion of nitrogen is through the am monia in exhaled air
C) The nitrogen content of proteins is almost uniformly 16%
D) Only the liver makes am monium
E) Only the liver makes urea

Accepted Answer

The nitrogen content of proteins is almost uniformly 16%, which allows for the estimation of protein catabolism by measuring urinary nitrogen. This is because proteins, when metabolized, release nitrogen, which is primarily excreted in the urine. By knowing the average nitrogen content of proteins, one can estimate the amount of protein catabolized based on the amount of nitrogen excreted.