Antiovulatory action of anordrin in the cynomolgus monkey (Macaca fascicularis)

Anordrin (2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta, 17 beta-diol dipropionate) was studied for its antiovulatory potency in the cynomolgus monkey. Anordrin, administered daily on days 9-13 of the menstrual cycle in doses of 4.0 and 8.0 mg/kg body weight, did not inhibit luteal activity in the cycle in which it was given, but delayed the development of ovarian follicles for 5 to 6 months. When a single low dose (0.1 or 0.2 mg/kg b.w.) was administered during the first 3 days of the menstrual cycle, follicular maturation was delayed such that luteal activity was not observed for an average of 26 and 39 days, respectively, and pregnanediol in the ensuing luteal phases was significantly decreased. Anordrin appears to inhibit follicular development when given during the stage of follicular recruitment.