Inhibiting Kiss1 Neurons with Kappa Opioid Receptor Agonists to Treat Polycystic Ovary Syndrome and Vasomotor Symptoms

Context Recent evidence suggests that vasomotor symptoms (VMS) or hot flashes in the postmenopausal reproductive state and polycystic ovary syndrome (PCOS) in the premenopausal reproductive state emanate from the hyperactivity of Kiss1 neurons in the hypothalamic infundibular/arcuate nucleus (KNDy neurons). Objective We demonstrate in 2 murine models simulating menopause and PCOS that a peripherally-restricted kappa receptor agonist (PRKA) inhibits hyperactive KNDy neurons (accessible from outside the blood brain barrier) and impedes their down-stream effects. Design Case/control. Setting Academic medical center. Participants Mice. Interventions Administration of peripherally-restricted kappa receptor agonists and frequent blood sampling to determine hormone release, and body temperature. Main outcome measures LH pulse parameters and body temperature. Results First, chronic administration of a PRKA to OVX mice with experimentally-induced hyperactivity of KNDy neurons reduces the animals' elevated body temperature, mean plasma LH level, and mean peak LH per pulse. Second, chronic administration of a PRKA to a murine model of PCOS, having elevated plasma testosterone levels and irregular ovarian cycles, suppresses circulating levels of LH and testosterone and restores normal ovarian cyclicity. Conclusion The inhibition of Kiss1 neuronal activity by activation of kappa receptors shows promise as a novel therapeutic approach to treat both VMS and PCOS in humans.