When 6-week-old rats fed normal diet (22% protein) were transferred to 10 and
7 5 % protein diet, the levels of urea cycle enzymes showed decreases and increases respectively.
The activities expressed as units per gram wet weight of liver had not stabilized after 7 days
on the new diet; the corresponding specific activities were closer to leveling off. Four daily
injections of cortisol raised CPS, ASS, and arginase. The percentage increases were greater on
a 10 than on a 75% protein diet. Adrenalectomy of rats fed 10% protein decreased all urea
cycle enzymes; on 7 5 % protein, only arginase decreased. All enzymes could be raised to control
levels within 24 h by three injections of cortisol. Thyroxine produced only slight increases
in urea cycle enzymes. On a 10% protein diet, all five enzymes were raised by thyroidectomy,
and further raised by injection of thyroxine.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.