Effect of androgens on the ovarian morphology of the hypophysectomized rat.

Experiments were designed to study the short-term effects of androgens on ovarian follicular morphology in immature, hypophysectomized rats. Rats were given 1 mg diethylstilbestrol (DES) daily for 5 days. On the fifth day, they were treated with 5-alpha-dihydrotestosterone (DHT), testosterone (T), and flutamide metabolite, alpha, alpha, alpha-trifluoro-2-methyl-4'-nitro-m-lactotoluidide (FM) alone and in combination and killed 24 hr later. One group of rats received DES alone. Ovarian serial sections (5 mum) were observed in each treatment for the presence of pyknotic nuclei as an index of atresia. Diameter of the follicles was measured, a percentage of atretic follicles was calculated, and the data were analyzed for all size follicles, follicles 150 mum or less (small), and follicles measuring over 150 mum (large). The results show that DHT and DHT plus T increased follicular atresia when all follicle sizes were considered. None of the treatments significantly changed follicular atresia in small follicles. In large follicles, both DHT and T increased follicular atresia. Furthermore, FM prevented T-induced atresia while by itself FM had no effect on follicular morphology. That the FM decreased the action of T in promoting atresia adds support to the conclusion that T promotes atresia by inhibiting the follicular growth promoting action of DES in the ovary. Also, this study shows that DHT promotes follicular atresia.