We hypothesized that putative anorectic and orexigenic peptides control the motivation to engage in either ingestive or sex behaviors, and these peptides function to optimize reproductive success in environments where energy fluctuates. Here, the putative orexigenic peptide, gonadotropin-inhibiting hormone (GnIH, also known as RFamide-related peptide-3), and the putative anorectic hormones lept...

Introduction: Gonadotropin inhibitory hormone (GnIH) and Agouti-related peptide (AgRP) are orexigenic peptides expressed in the arcuate nucleus (Arc) of the hypothalamus in the ewe. In addition, effects of GnIH and AgRP on the regulation of gonadotropin releasing hormone secretion have been shown in some mammals. The objective of the present study was to investigate the coexpression of GnIH ...

The existence of a hypothalamic gonadotropin-inhibiting system has been elusive. A neuropeptide named gonadotropin-inhibitory hormone (GnIH, SIKPSAYLPLRF-NH(2)) which directly inhibits gonadotropin synthesis and release from the pituitary was recently identified in quail hypothalamus. Here we identify GnIH homologs in the human hypothalamus and characterize their distribution and biological act...

introduction: gonadotropin inhibitory hormone (gnih) is believed to be an inhibitor of gonadotropin releasing hormone (gnrh) secretion. the role of gnih in lactational inhibition of gonadotropin secretion is not well known therefore, the aim of the present study was to evaluate the effect of lactation on expression of gnih in these nuclei of lactating and non-lactating rats. methods: ten postpa...

The reproductive system is controlled by gonadotropin releasing hormone (GnRH) secretion from the brain, which is finely modulated by a number of factors including gonadal sex steroids. GnRH cells do not express estrogen receptor α, but feedback is transmitted by neurons that are at least 'one step back' from the GnRH cells. Modulation by season, stress and nutrition are effected by neuronal pa...

Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that inhibits gonadotropin secretion and socio-sexual behaviours. Oestrogen (neuroestrogen) synthesized in the brain from androgen by aromatase regulates male socio-sexual behaviours. Here we show that GnIH directly activates aromatase and increases neuroestrogen synthesis in the preoptic area (POA) and inhibits socio-sexual ...

Seasonally breeding birds detect environmental signals, such as light, temperature, food availability, and presence of mates to time reproduction. Hypothalamic neurons integrate external and internal signals, and regulate reproduction by releasing neurohormones to the pituitary gland. The pituitary gland synthesizes and releases gonadotropins which in turn act on the gonads to stimulate gametog...

introduction: gonadotropin inhibitory hormone (gnih) and agouti-related peptide (agrp) are orexigenic peptides expressed in the arcuate nucleus (arc) of the hypothalamus in the ewe. in addition, effects of gnih and agrp on the regulation of gonadotropin releasing hormone secretion have been shown in some mammals. the objective of the present study was to investigate the coexpression of gnih and...

introduction: gonadotropin inhibitory hormone (gnih) has been known as a key inhibitor of the secretion of gonadotropin releasing hormone (gnrh). ewe has estrous cycles comprising of follicular and luteal phases. follicular phase is in turn divided into proestrous and estrous phases. blood level of lh increases in follicular and decreases in luteal phases. the aim of the present study was to ev...

Introduction: Gonadotropin inhibitory hormone (GnIH) is believed to be an inhibitor of gonadotropin releasing hormone (GnRH) secretion. The role of GnIH in lactational inhibition of gonadotropin secretion is not well known therefore, the aim of the present study was to evaluate the effect of lactation on expression of GnIH in these nuclei of lactating and non-lactating rats. Methods: Ten po...