[Intensive conversion in vitro of 5 alpha-androstane-3-alpha, 17 beta-diol into 5 alpha-dihydrotestosterone in the anterior hypophysis of male rats].

When anterior hypophysis from male rats were incubated in the presence of tritiated 5 alpha-androstan-3 alpha, 17 beta-diol (3 alpha-diol), the major part of recovered pituitary radioactivity was constituted by 5 alpha-dihydrotestosterone (5 alpha-DHT). This steroid represented an average of 72% of total tissular radioactivity. In cytosol, the bound hormonal fraction was constituted by about 47% 5 alpha-DHT and 35% 3 alpha-diol, whereas free radioactivity contained 67% 5 alpha-DHT and 22% 3 alpha-diol. These results demonstrate an intensive conversion of 3 alpha-diol into 5 alpha-DHT and consequently that the transformation of 5 alpha-DHT into 3 alpha-diol is reversible. Thus it is reasonable to think that the biological action of 3 alpha-diol one can observe following in vivo or in vitro experiments is due, in fact, to its conversion into 5 alpha-DHT.