GnRH is the master neuropeptide that coordinates and regulates reproduction in all vertebrates and in some nonvertebrate species. Sixteen forms of GnRH have been isolated in brain. In the vast majority of species, two or more forms occur in anatomically and developmental distinct neuronal populations. In mammalian brain, two GnRH forms, mammalian (GnRH-I) and chicken-II (GnRH-II), exist. The di...

Gonadotrophin-releasing hormone (GnRH) neurones constitute the final output pathway of a neuronal network that controls the preovulatory luteinising hormone (LH) surge and ovulation. Throughout the reproductive cycle, several neurotransmitters stimulate and inhibit the activity of GnRH neurones, including oxytocin. The central administration of oxytocin antiserum abolishes the pro-oestrous LH s...

In vertebrates, gonadotropin-releasing hormone (GnRH) is a crucial decapeptide that activates the hypothalamic-pituitary-gonadal axis to ensure successful reproduction. Recently, a GnRH-like molecule has been isolated from a gastropod mollusk, Aplysia californica. This GnRH (ap-GnRH) is deduced to be an undecapeptide, and its function remains to be explored. Our previous study demonstrated that...

Several evidences supported the existence of melatonin effects on reproductive system in fish. In order to investigate whether melatonin is involved in the modulation of GnRH systems in the European sea bass, we have injected melatonin (0.5 µg/g body mass) in male specimens. The brain mRNA transcript levels of the three GnRH forms and the five GnRH receptors present in this species were determi...

Gonadotropin-releasing hormone (GnRH) is exclusively expressed in a unique population of hypothalamic neurons that controls reproductive function. GnRH gene expression is highly dynamic. Its transcriptional activity is regulated in a complex spatiotemporal manner during embryonic development and postnatal life. Although a variety of transcription factors have been identified as regulators of Gn...

GnRH acts via GnRH receptors (GnRH-R) in the pituitary to cause the release of gonadotropins that regulate vertebrate reproduction. In the teleost fish, Haplochromis burtoni, reproduction is socially regulated through the hypothalamus-pituitary-gonadal axis, making the pituitary GnRH-R a likely site of action for this control. As a first step toward understanding the role of GnRH-R in the socia...

Stimulation of pituitary gonadotropes by hypothalamic GnRH leads to the rapid expression of several immediate early genes that play key roles in orchestrating the response of the gonadotrope to hypothalamic stimuli. Elucidation of the signaling mechanisms that couple the GnRH receptor to this immediate early gene repertoire is critical for understanding the molecular basis of GnRH action. Here ...

The amino acid gamma-aminobutyric acid (GABA) plays an important role in the regulation of the GnRH neurons. We examined whether GABA depolarizes or hyperpolarizes GnRH neurons over postnatal development using gramicidin, perforated-patch electrophysiology combined with GnRH-LacZ transgenic mice in whom GnRH neurons can be made to fluoresce. The basic membrane properties and GABA responsiveness...

OBJECTIVE To review the physiologic functions and clinical significance of peripheral GnRH receptors. DESIGN Literature review. All peer-reviewed journal articles published before 2010 on peripheral GnRH receptors were searched for in the Pubmed database, and relevant findings were summarized. RESULT(S) Peripheral GnRH/GnRH receptor systems may serve as regulators of hCG synthesis and impla...