Seasonal Variation in Reproductive Hormones of Rhesus Monkeys: Anovulatory and Short Luteal Phase Menstrual Cycles1

Abstract

Rhesus monkeys show a period of low fertility and decreased ovulation during the spring and summer months. In the present study, menstrual events and reproductive hormone concentrations associated with this period were examined to determine if secretion of gonadotropins was lower in the anovulatory cycle and if the level of gonadotropin was related to secretion of estrogen.