The ovarian cycle and control of ovulation



The ovarian cycle of primates is a sequence of events reflecting follicular growth and development, the ovulation of a mature oocyte and the formation of a functional corpus luteum. A typical cycle generally consists of three phases: (1) the follicular or proliferative phase, (2) ovulation and (3) the luteal or secretory phase. Within this general pattern exists considerable species variation in terms of cycle length, timing of ovulation, presence or absence of menstruation and influence of season.

Details of the basic physiological mechanisms controlling cyclic ovarian function in primates are known for only a few species. Concentrating on information derived from studies in women and in rhesus and marmoset monkeys, this paper examines some of the hormonal mechanisms underlying the primate ovarian cycle with particular reference to the factors controlling preovulatory follicular development during the follicular phase.