Steroid 17-beta-oxidoreductase activity in the rabbit central nervous system and adenohypophysis.

Abstract

Recent in-vivo and in-vitro experiments have revealed a discordance in the ability of the brain and adenohypophysis from man, monkeys, rats and rabbits to form oestrone from testosterone, and oestradiol-17β from androstenedione (Naftolin, Ryan & Petro, 1971a, b; Flores, Naftolin & Ryan, 1973; Flores, Naftolin, Ryan & White, 1973; Reddy, Naftolin & Ryan, 1973). To examine this question further, central tissues from untreated adult virgin female and male New Zealand White rabbits were incubated in vitro with [3H]oestrone, [14C]androstenedione or [14C]testosterone under conditions identical to those described in the above reports. After dissection, the tissues were homogenized and incubated with approximately 2 μCi of one of the above steroids (all obtained from New England Nuclear Corp.) in the presence of an NADPH-generating system, except for the omission of glucose 6-phosphate and glucose 6-phosphate dehydrogenase during the testosterone incubations. After incubation of oestrone, oestradiol-17β was