During the past years it has been demonstrated that gonadotropin-releasing hormone (GnRH) has specific actions on extra pituitary tissues such as placenta, breast and ovary. Synthetic GnRH agonists (GnRH-a) are frequently used in human infertility treatments. These molecules reduce the endogenous secretion of gonadotropins by a mechanism of pituitary down-regulation. In cycles of ovarian hyperstimulation in patients undergoing assisted fertilization, they have been administered together with gonadotropins to inhibit the endogenous LH peak and improve follicular recruitment. However, higher doses of gonadotropins are necessary to induce hyperstimulation when GnRH-a are administered. These observations suggest that the lower responsiveness to gonadotropins could be due to an inhibitory effect on the ovary. There is now increasing evidence that these agonists act directly on the follicular development. Some evidences support the idea that gonadal GnRH-like peptide are involved in follicular apoptosis (programmed cell death) It is, therefore, of great interest to study the role of GnRH-a on the steroidogenic and apoptotic ovarian process.