Don P. Wolf

In vitro fertilization and embryo transfer in primates

This volume contains the proceedings of a symposium which provides an in-depth analysis of current IVF-ET technology as applied to nonhuman primates. Although IVF-ET is now considered standard treatment for several categories of human infertility, a nonhuman primate model remains highly desirable for the study of reproductive and developmental processes, as well as for the establishment of improved disease models for medical research and the preservation of endangered nonhuman primate species. A better understanding of the primate reproductive system is thus essential to facilitate a global effort to control human population and to aid childless families attempting to overcome their infertility.

Stimulation of Follicle and Oocyte Development in Macaques for IVF Procedures

In many primate species the interactions between and within components of the hypothalamic-pituitary-ovarian axis ensure the maturation of a single follicle and the timely release of one oocyte capable of fertilization around the middle of the menstrual cycle. Knowledge of the processes involved in growth, selection, maturation, and ovulation of the dominant follicle has increased substantially in recent years, particularly from experimental studies in rhesus monkeys (1, 2). The importance of the pituitary gonadotropins, follicle stimulating hormone (FSH) and luteinizing hormone (LH), in the folliculo- and gametogenic functions of the ovary have been recognized for over 50 years (3, 4), but recent manipulations to stimulate follicular development have added new information on the processes and events controlled by FSH and LH (5, 6). It is clear that methods that elevate circulating levels of endogenous or exogenous gonadotropins (FSH and LH) override the mechanisms that select a single dominant follicle and stimulate the development of multiple follicles and their enclosed oocytes.

IVF-ET in Old World Monkeys

IVF-ET is an emerging technology in nonhuman primates (NHP) since it is based on relatively limited experience in only a few species. Thus, while successful protocols are available for rhesus and cynomolgus monkeys, consistent or wide-spread application is not yet the order of the day. Undoubtedly, substantial species-dependent differences will be discovered, such as the extended menstrual cycle length recently described by us in Macaca nigra (1). This picture is in marked contrast with the extensive experience base now available in the human.