Effects of RMI 12,936 on some reproductive processes in the female golden hamster.

A single subcutaneous injection of 2 mg RMI 12,936 (17 beta-hydroxy-7 alpha-methylandrost-5-en-3-one) given a day after estrus disrupted estrous cycle for over 30 days and inhibited ovulation in 100 percent of treated Golden hamsters. Administration of RMI 12,936 (2 mg) on Day 6 of pregnancy caused termination of pregnancy within 4 days of treatment. In association with the termination of pregnancy was a significant reduction in the concentrations of progesterone and estradiol-17 beta together with an elevated testosterone level. After termination of pregnancy by RMI 12,936, the hamsters remained sexually receptive for 4 weeks but failed to conceive. It is concluded that RMI 12,936 causes termination of pregnancy due to an induction of functional luteolysis.