Contraceptive steroids and sexual activity.

Abstract

Since rhesus monkeys have a true menstrual cycle of 28 days and sexual behavior of males is observed to change in response to the female cycle oral contraceptive steroids were administered to monkeys to measure sexual behavior objectively. 2 sterilized females were exposed to 2 males and the number of thrusts and ejaculations were recorded for 1 hour per pair 2-3 times per week. (Fewer thrusts indicate high sexual stimulation in these monkeys.) .05 mg mestranol and 1.0 mg ethinyl diacetate were injected daily in the females for 21 days followed by 6 days without treatment 6 months; then a sequential regimen of .05 mg mestranol for 11 days and .75 mg chlormadinone acetate for the next 10 days followed by 7 days without treatment was given for 6 months. Male ejaculatory capacity decreased progressively with the combined regimen. Number of thrusts to ejaculation increased accordingly. The sequential regimen decreased male ejaculatory performance to a lesser extent and this decrease was not progressive.