In perifused immortalized GnRH neurons (GT1-7), simultaneous measurements of GnRH and cAMP revealed that the secretory profiles for both GnRH and cAMP are pulsatile. An analysis of GnRH and cAMP pulses in 16 independent experiments revealed that 25% of pulses coincide. Inversion of the peak and nadir levels was found in 33% and random relationship between GnRH and cAMP found in 42% of analyzed ...

A gonadotropin-releasing hormone (GnRH)-binding inhibitor (GnRH-BI) was purified from bovine ovaries and identified as histone H2A. In the present studies, the biological effects of partially purified and purified ovarian GnRH-BI, as well as calf thymus histone H2A, were examined in rat ovarian cells. Since GnRH has direct antigonadotropic actions on these cells, the effects on luteinizing horm...

Multiple GnRH receptors are known to exist in nonmammalian species, but it is uncertain which receptor type regulates reproduction via the hypothalamic-pituitary-gonadal axis. The teleost fish, Astatotilapia burtoni, is useful for identifying the GnRH receptor responsible for reproduction, because only territorial males reproduce. We have cloned a second GnRH receptor in A. burtoni, GnRH-R1(SHS...

GnRH neuron activity is dependent on gonadal steroid hormone feedback. Altered synaptic input may be one mechanism by which steroids modify GnRH neuron activity. In other neuronal populations, steroid hormones have been shown to elicit profound effects on dendritic spine density, a measure of excitatory synaptic input. The present study examined gonadal steroid feedback effects on GnRH neuron s...

The two living representatives of the most ancient vertebrates, Agnathans, are lamprey and hagfish. Using immunological methods, we identified gonadotropin-releasing hormone (GnRH)-like molecules in the lamprey brain, but not hagfish. The lamprey GnRH was detected poorly by antisera directed at the C-terminus, suggesting that a C-terminal amino acid substitution may have occurred in the lamprey...

Fertility depends on the correct maturation and function of approximately 800 gonadotropin-releasing hormone (GnRH) neurons in the brain. GnRH neurons are at the apex of the hypothalamic-pituitary-gonadal axis that regulates fertility. In adulthood, GnRH neurons are scattered throughout the anterior hypothalamic area and project to the median eminence, where GnRH is released into the portal vas...

OBJECTIVE To elucidate the physiologic mechanism responsible for the supraphysiologic gonadotropin release from the pituitary induced by gonadotropin-releasing hormone (GnRH) agonist in female rats primed with GnRH antagonist. DESIGN Controlled experimental intervention. SETTING Government research facility. ANIMAL(S) Forty 8-week-old Sprague-Dawley rats. INTERVENTION(S) Forty oophorect...

Gonadotropin-releasing hormone (GnRH) is a decapeptide widely known for its role in regulating reproduction by serving as a signal from the hypothalamus to pituitary gonadotropes. In addition to hypothalamic GnRH (GnRH-I), a second GnRH form (pGln-His-Trp-Ser-His-Gly-Trp-Tyr-Pro-Gly; GnRH-II) with unknown function has been localized to the midbrain of many vertebrates. We show here that a gene ...

Many researches on the change and protective effects of estrogen and its receptor in hippocampus with ischemia-reperfusion injury have been done in recent years; the study on the change of GnRH and its receptor in hippocampus with ischemia-reperfusion injury has not been seen yet. This study used immunohistochemistry and in situ hybridization method, together with an image analysis system to ob...

GnRH is an evolutionarily conserved neuropeptide, of which there are multiple structural variants; the function of the most widespread variant, GnRH-II, remains undefined. GnRH-II may affect reproductive behavior; GnRH-II administration to female musk shrews reinstates mating behavior previously inhibited by food restriction. To determine whether this action of GnRH-II is universal, we conducte...