The G protein-coupled receptor GPR54, and its peptide ligand kisspeptin (Kp), are crucial for the induction and maintenance of mammalian reproductive function. GPR54 is expressed by GnRH neurons and is directly activated by Kp to stimulate GnRH release. We hypothesized that Kp may be able to act at the GnRH nerve terminals located in the mediobasal hypothalamus (MBH) region. To test this hypoth...

During development, an increase in gonadotropin-releasing hormone (GnRH) release occurs that is critical for the initiation of puberty. This increase is attributable, at least in part, to activation of the GnRH neurosecretory system by inputs from neurotransmitters, such as glutamate, acting via NMDA receptors. We examined changes in GnRH and NMDA-R1 gene expression by RNase protection assay of...

Close to 30 forms of gonadotropin releasing hormone (GnRH) and at least five GnRH receptors have been identified in a wide variety of vertebrates and some invertebrates. One form, now called GnRH II, has the broadest distribution and the most ancient and conserved phylogeny. The distribution of the neurons that produce this peptide are completely nonoverlapping with any other GnRH forms. Fibers...

Mice were generated expressing green fluorescent protein (GFP) under the control of the gonadotropin-releasing hormone (GnRH) promoter. Green fluorescence was observed in, and restricted to, GnRH-immunopositive neuronal somata in the olfactory bulb, ganglion terminale, septal nuclei, diagonal band of Broca (DBB), preoptic area (POA), and caudal hypothalamus, as well as GnRH neuronal dendrites a...

The effect of endogenous gamma-aminobutyric acid (GABA)(A) receptor-mediated signaling on the excitability of adult male and female GnRH neurons was examined using gramicidin perforated-patch electrophysiology in GnRH-LacZ and GnRH-GFP (green fluorescent protein) transgenic mouse models. In both lines of mice, approximately 80% of GnRH neurons (n = 42) responded to the selective GABA(A) recepto...

Estradiol plays a pivotal role in the control of gonadotropin-releasing hormone (GnRH) neuronal function and female reproduction. While positive and negative feedback actions of estradiol that enhance and suppress release of GnRH and LH are primarily mediated through estrogen receptor alpha located in interneurons, a series of recent studies in our laboratory indicate that rapid excitatory acti...

Sir, It has been more than 10 years since safe and effective gonadotrophinreleasing hormone (GnRH) antagonists became available for use in controlled ovarian stimulation (COS) cycles. In 2000, we noted that there was an inconsistency with how researchers in this field describe the mechanism of action of GnRH antagonists (Mannaerts and Gordon, 2000). Unfortunately, there is continued misuse of t...

In the present study, both lamprey GnRH-I and -III stimulated steroidogenesis and induced ovulation in adult female sea lampreys during their final reproductive stage. One injection of lamprey GnRH-III at 0.1 or 0.2 microg/g lamprey stimulated plasma estradiol levels in lampreys held at each of three water temperatures, 13 degrees , 17 degrees , and 19 degrees , corresponding to increasing stag...

The GnRH analogue (agonist and antagonist GnRH) changed ovarian stimulation. On the one hand, it improved chances of pregnancy to obtain more oocytes and better embryos. This leads to an ovarian hyper-response, which can be complicated by the ovarian hyperstimulation syndrome (OHSS). On the other hand, the GnRH analogue can prevent the incidence of OHSS: GnRH antagonist protocols, GnRH agonist ...