Ursula Kaiser, MD

Institution: Brigham and Women's Hospital
Research: Neuroendocrine Control of Reproduction and Metabolism
Grants & Publications: Harvard Catalyst
Categories: BWH

Diabetes mellitus and other metabolic and nutritional disorders can lead to a number of complications, which include a major impact on reproductive maturation and fertility. We are interested in the intersection of neuroendocrine control of reproductive development and function with that of metabolism. The hypothalamic pathways by which gonadotropin-releasing hormone (GnRH) neurons are reactivated at puberty and by which the precise periodic pulsatile release of GnRH is regulated are closely intertwined with those that sense energy balance and regulate appetite and metabolism. As one example, congenital leptin deficiency is associated with severe obesity as well as with hypogonadotropic hypogonadism that responds to leptin administration. Furthermore, leptin administration to women with hypothalamic amenorrhea improves reproductive function. Similarly, many other genes implicated in hypothalamic pathways of appetite and energy metabolism are also associated with hypogonadotropic hypogonadism when deleted or mutated in patients or in animal models. We are interested in dissecting the pathways by which central regulation of metabolism and reproduction interconnect. A recent avenue of our investigation is the characterization of the functional roles of kisspeptin and neurokinin B in the regulation of GnRH release and in the neuroendocrine regulation of reproductive function. Studies have demonstrated that kisspeptin and its receptor are downstream of leptin, as administration of kisspeptin in leptin-deficient animal models results in recovery of gonadotropin secretion. We are interested in mapping the neural pathways that link leptin action to kisspeptin and/or GnRH neurons. An additional area of interest is polycystic ovarian syndrome, a reproductive disorder associated with obesity and insulin resistance in which GnRH pulse frequency is increased, resulting in altered ratios of luteinizing hormone and follicle-stimulating hormone secretion and hence irregular menses, anovulation and infertility. Treatment with insulin sensitizing agents results in improvement in these reproductive parameters. It is expected that these studies will provide new insights into the links between energy balance and reproductive function, and lead to improved management of disorders of reproductive function.