Effect of steroid hormones on age dependent changes in rat arginase isoenzymes.

Age dependent changes in rat liver and kidney arginase isoenzymes from day 1 to 73 weeks have been studied. It has been observed that total liver arginase activity (activity/liver) increases with age, but there is no appreciable change in the proportions of isoenzymes, their pH optima, electrophoretic mobilities and inhibition characteristics, although Km increases with age. Corticosterone induces liver arginase activity and the degree of induction decreases with age. The hormone has no effect on kidney arginase. Testosterone treatment, on the other hand, induces kidney arginase without any effect on liver enzyme.