The ovarian cycle

Throughout adult reproductive years, the structural composition and hormona l activity of the ovary are continually changing. The two major functions o f the adult ovary, the synthesis of ser; steroids and the release of mature ovum every 28-30 days are closely interrelated. Ovaries, in particular, se crete three types of steroids, namely estradiol, progesterone and androsten edione, which participate to complex controls that evolve over time during the ovarian cycle with negative as well as positive effects. Several peptid es are also synthetized by various ovarian cells and play a role in the ova rian function. These include, besides trophic factors, inhibin and activin. The functionning of the ovary depends on a complex feedback mechanism invo lving the hypothalamus and the anterior pituitary. This paper provides an o verview of the different events of the ovarian cycle and their regulation i n women.