Hypothalamic gonadotropin releasing hormone: physiologic and clinical considerations

Despite the efforts of a large number of investigators, the role of GnRH in clinical gynecology is uncertain. At present, its greatest utility is in research directed toward the understanding of hypothalamic-pituitary interrelationships. However, a clear understanding of the hypothalamic control of gonadotropin secretion awaits the actual measurement of the secretion of GnRH by the hypothalamus. In addition, a better understanding of the ability of the pituitary to secrete gonadotropins in various disorders of menstruation and maturation will probably be achieved through the determination of the capacity of the pituitary to synthesize as well as release gonadotropins in response to GnRH. Such determinations will probably utilize repeated or continuous infusions of GnRH rather than the currently more popular single injection technique. Finally, GnRH may be useful in the induction of ovulation. A definition of its role in ovulation induction awaits the results of additional clinical studies. Understanding of the nature of hypothalamic control of the pituitary is as yet incomplete. The availability of hypothalamic releasing factors will make it possible to study in greater detail the mechanisms by which the fine regulation of the endocrine system is achieved.