Effects of the neuropeptide Y on estradiol and progesterone secretion by human granulosa cells in culture

Objective: To investigate the possible effects of neuropeptide Y on steroid release by human granulosa cells in culture. Design: Prospective study. Setting: A university laboratory and the division of obstetrics and gynecology in a hospital. Patient(s): Sixteen normally ovulating women. Intervention(s): Ovulation induction for IVF-ET with an LH-releasing hormone analogue and gonadotropins. Main Outcome Measure(s): E 2 and progesterone were assayed in the media conditioned by granulosa cells with the use of a double-antibody RIA. Result(s): Neuropeptide Y stimulates E 2 production in a dose-dependent fashion. Preincubation for 3 hours with hCG led to a statistically significant increase in neuropeptide Y–induced E 2 secretion. In contrast, whereas 3 hours of preincubation with 10 −7 mol/L of neuropeptide Y did not elicit a statistically significant increase in hCG-induced E 2 secretion, coincubation for 48 hours significantly increased hCG-stimulated secretion. Unlike E 2, progesterone secretion did not undergo any statistically significant or dose-dependent variation after treatment with neuropeptide Y. Conclusion(s): Neuropeptide Y plays a role in human ovarian steroidogenesis directly at the level of the granulosa cells of the follicles in the early stage of luteinization. In this way, neuropeptide Y could play an important role in controlling the positive feedback effect exerted by the ovarian steroids on LH-releasing hormone and gonadotropins in humans.