Antagonism of the actions of estrogens, androgens and progesterone by anordrin (2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta, 17 beta-diol dipropionate).

Anordrin, an antifertility agent that is an antiestrogen with weak estrogenic activity, has been studied to further characterize its hormonal activities. A dose of 2.0 micrograms/mouse X day for 7 days did not increase the uterine content of protein, but it did inhibit to a small extent the effect of administered estradiol-17 beta on uterine protein content and more significantly the effect of estradiol-17 beta on the uterine content of progesterone receptors. Anordrin also decreased serum corticosteroid-binding globulin levels. Administration of an average daily dose of 160 micrograms/day of anordrin to intact male mice had no effect on weights of kidney, testis, or seminal vesicle after 10 days, but seminal vesicle weight was significantly decreased after 30 days at a slightly lower dose. Similarly, anordrin inhibited the increase in seminal vesicle weight induced by testosterone propionate treatment of castrated mice. In female mice anordrin failed to maintain deciduomata and blocked the ability of progesterone (2.0 mg/mouse X day) to do so. However, anordrin did not compete with the androgen [3H]R1881 for binding in kidney cytosol or with the progestin [3H]R5020 for uterine receptor sites. Anordrin also did not compete with [3H]corticosterone for binding to serum proteins.