Ovulation induction using 'pure' follicle-stimulating hormone in monkeys

Recently we have demonstrated that administration of a 'pure' follicle-stimulating hormone (FSH) preparation (Urofollitropin, Serono Laboratories, Inc., Randolph, MA) to normally cycling monkeys induces multiple follicular development. In these earlier studies, a spontaneous luteinizing hormone (LH) surge was uncommon; no attempt was made to induce ovulation with exogenous human chorionic gonadotropin (hCG). In this study, multiple follicular development and ovulation were induced in normally cycling monkeys by daily follicular phase administration of 'pure' FSH followed by hCG. Short-term administration of 'pure' FSh during the early or late follicular phase also induced multiple follicular development; however, multiple ovulations subsequent to a spontaneous LH surge never occurred. One monkey treated in the late follicular phase did demonstrate a spontaneous LH surge and single ovulation following late follicular phase FSH treatment. These findings suggest that administration of 'pure' FSH alone, to enhance the natural ovarian cycle, may be useful for inducing multiple follicular development, but that ovulatory competence is usually dependent on exogenous LH/hCG.