ABSTRACT
LUTEINIZING HORMONE-RELEASING HORMONE The neurohormone involved in regulating the synthesis and release of both folliclestimulating hormone (FSH) and luteinizing hormone (LH) is gonadotropin-releasing hormone (GnRH), also known as luteinizing hormonereleasing hormone (LHRH). It is a decapeptide secreted from the LHRH neurons of the hypothalamus into the portal vessels. LHRH modulates both LH and FSH, neither of them selectively. The half-life of LHRH is 2-4 min. It is secreted as a pulse every hour during the follicular phase and every 3 h during the luteal phase. Its main function is to promote synthesis, storage and release of gonadotropins. Pulsatile secretion of LHRH leads to pulsatile release of LH and FSH. Therefore, hypothalamic LHRH neurons regulate the synthesis and secretion of FSH and LH by the anterior pituitary. Alteration of the output of FSH and LH can be achieved by increasing or decreasing the amplitude or frequency of LHRH pulses.
