Anti-Gonadal Hormone Activity of 1lα-Hydroxyproges terone

Summary 1. U-0384 (1lα-hydroxyprogesterone) partially counteracted the effects of exogenous estradiol in stimulating the uteri of ovariectomized rats and the seminal vesicles of castrated male rats. This compound also decreased the hypertrophy of the seminal vesicles, prostate, and levator ani muscle in castrated males injected with testosterone propionate. In intact rats U-0384 decreased the weight of the sex accessories by its anti-gonadal hormone activity and through its inhibitory effect on gonadotrophic hormone secretion. 2. This steroid has 110 estrogenic, androgenic, or progestational activity in the amounts assayed. This compound, when injected in large amounts,. produced only slight adrenal atrophy and no thymic involution, and can, therefore, be presumed to have very little or no adrenal cortical hormone activity. 3. Although the anti-estrogen and anti-androgen activity of this new steroid is limilted in animals, inasmuch as it lacks other gonadal hormone effects, it may be effective in therapy of some pathological conditions in which a reduction of endogenous sex hormones is considered desirable.