Gonadotropin-releasing hormone (GnRH) controls the reproductive physiology and behavior of vertebrates by stimulating synthesis and release of gonadotropin from the pituitary gland. In 2000, another hypothalamic neuropeptide, gonadotropin-inhibitory hormone (GnIH), was discovered in quail and found to be an inhibiting factor for gonadotropin release. GnIH homologs are present in the brains of v...

An adequate frequency of gonadotropin-releasing hormone (GnRH) pulses appears to be important for physiological gonadotropin secretion. However, limited information exists on the exact role of this parameter in the regulation of the human menstrual cycle. Thus we studied gonadotropin and gonadal steroid secretion in 32 women with primary hypogonadotropic amenorrhea who received pulsatile GnRH (...

OBJECTIVE To find the time of the serum gonadotropin peak after depot leuprolide injection in children and to show that depot leuprolide therapy can be monitored by measuring serum luteinizing hormone (LH) immediately after injections. STUDY DESIGN We measured concentrations of leuprolide, LH, and follicle-stimulating hormone (FSH) at multiple time points before and after the first dose of de...

We previously isolated a novel dodecapeptide containing a C-terminal -Arg-Phe-NH(2) sequence, SIKPSAYLPLRF-NH(2) (RFamide peptide), from the quail brain. This quail RFamide peptide was shown to decrease gonadotropin release from the cultured anterior pituitary and to be located at least in the quail hypothalamo-hypophysial system. We therefore designated this RFamide peptide gonadotropin inhibi...

M.J. Zamiri Department of Animal Science, College of Agriculture, Shiraz University, Shiraz, Iran [email protected] Introduction Since the discovery of kisspeptin and gonadotropin-inhibitory hormone (GnIH) our understanding of the vertebrate reproductive physiology has greatly increased. Gonadotropinreleasing hormones (GnRH) is a hypothalamic decapeptide secreted into the hypothalamohypophysea...

Seasonal breeding is widespread in vertebrates and involves sequential development of the gonads, onset of breeding activities (e.g. cycling in females) and then termination resulting in regression of the reproductive system. Whereas males generally show complete spermatogenesis prior to and after onset of breeding, females of many vertebrate species show only partial ovarian development and ma...

To assess the effects of a gonadotropin-releasing hormone agonist, [D-Leu6,des-Gly10] luteinizing hormone-releasing hormone ethylamide, in ameliorating the damage caused by ionizing radiation, gonadotropin-releasing hormone agonist was administered to rats from day 22 to 37 of age in doses of 0.1, 0.4, and 1.0 microgram/day or vehicle and the rats were sacrificed on day 44 of age. There were no...

Spermatogenesis is thought to critically depend on the high intratesticular testosterone (T) levels induced by gonadotropic hormones. Strategies for hormonal male contraception are based on disruption of this regulatory mechanism through blockage of gonadotropin secretion. Although exogenous T or T plus progestin treatments efficiently block gonadotropin secretion and suppress testicular T prod...