Inhibition of testosterone metabolism by medrogestone in rat ventral prostate in vivo and in vitro.

Medrogestone (MDG), viz., 6,17-dimethyl-4,6-pregnadiene-3,20-dione (Colprone), a synthetic compound with progestational and antiandrogenic properties was studied for its effect on the conversion of testosterone (T) to 5 alpha-dihydrotestosterone (DHT) and 5 alpha-androstane-3 alpha(beta)-17 beta-diol (Adiol) by ventral prostatic preparations of the rat. MDG, 20 mg/kg b.w./day s.c. for 14 days, inhibited the conversion of T to DHT by ventral prostatic homogenates and cytoplasm and at the same dose and route, but for 28 days, it reduced the conversion of T to DHT by ventral prostatic nuclei and T to Adiol by ventral prostatic cytoplasm and nuclei. MDG, from 1 X 10(-4) to 1 X 0(-5) M final concentration in vitro, induced dose-dependent decreases in the conversions of T to DHT and Adiol by ventral prostatic nuclei.