Hepatic Metabolism and the Anti-Androgenic Activity of Cyproterone Acetate.

Abstract

Summary and conclusions The effects of splenic vs. subcutaneous depots of pellets of an anti-androgen, cyproterone acetate (Cyp A), were studied in castrate rats receiving daily injections of .1 mg of testosterone pro-pionate per 100 g body weight, Mean loss of weight of pellets was similar in both sites, indicating comparable absorption. Inhibition of growth of seminal vesicles was significantly less with splenic than with subcutaneous depots of Cyp A (P<.05, Exp 1; P<.001, Exp 2). These data provide evidence that (a) this compound does not exert its anti-androgenic effects by increasing the inacti-vation of testosterone propionate in the liver, and that (b) Cyp A can be destroyed in the liver before producing systemic effects as an anti-androgen. The effectiveness of Cyp A as an anti-androgen was shown by a 40% reduction in androgenic response in studies employing a ratio of 2 parts of Cyp A (supplied by pellets) to 1 part of testosterone propionate (supplied in oil).