No inhibitory effects of danazol estrogen production by ovaries of hypophysectomized rats stimulated by gonadotropins.

The effects of danazol on estrogen production by rat ovaries were investigated. Hypophysectomized immature female rats were injected daily with 2.5 or 5 IU of pregnant mare serum gonadotropin (PMS) and simultaneously daily given vehicle only or danazol (100 mg/kg body weight) for 14 days. Danazol did not decrease the activities of 3 beta-hydroxysteroid dehydrogenase, 17 alpha-hydroxylase, 17, 20-lyase and aromatase in the ovaries of rats stimulated by 5IU of PMS. Danazol also did not decrease the activities of 3 beta-hydroxysteroid dehydrogenase and aromatase, and the production of aromatizable androgens (androstenedione plus testosterone) from progesterone in the ovaries of rats stimulated by 2.5 IU of PMS. In accordance with these results, danazol did not reduce the level of estradiol-17 beta in the sera of rats stimulated by 2.5 and 5 IU of PMS. The present results suggest that danazol does not inhibit estrogen production by the rat ovary through its direct action on the ovary.