scholarly journals RFamide-Related Peptide-3 Receptor Gene Expression in GnRH and Kisspeptin Neurons and GnRH-Dependent Mechanism of Action

Endocrinology ◽  
2012 ◽  
Vol 153 (8) ◽  
pp. 3770-3779 ◽  
Author(s):  
Mohammed Z. Rizwan ◽  
Matthew C. Poling ◽  
Maggie Corr ◽  
Pamela A. Cornes ◽  
Rachael A. Augustine ◽  
...  
Keyword(s):  
Neuronal Network ◽  
Receptor Gene ◽  
Male Rats ◽  
Gonadotropin Secretion ◽  
Female Mice ◽  
Related Peptide ◽  
Gnrh Neurons ◽  
Lh Secretion ◽  
G Protein Coupled

RFamide-related peptide-3 (RFRP-3) is known to inhibit the activity of GnRH neurons. It is not yet clear whether its G protein-coupled receptors, GPR147 and GPR74, are present on GnRH neurons or on afferent inputs of the GnRH neuronal network or whether RFRP-3 can inhibit gonadotropin secretion independently of GnRH. We tested the following: 1) whether GnRH is essential for the effects of RFRP-3 on LH secretion; 2) whether RFRP-3 neurons project to GnRH and rostral periventricular kisspeptin neurons in mice, and 3) whether Gpr147 and Gpr74 are expressed by these neurons. Intravenous treatment with the GPR147 antagonist RF9 increased plasma LH concentration in castrated male rats but was unable to do so in the presence of the GnRH antagonist cetrorelix. Dual-label immunohistochemistry revealed that approximately 26% of GnRH neurons from male and diestrous female mice were apposed by RFRP-3 fibers, and 19% of kisspeptin neurons from proestrous female mice were apposed by RFRP-3 fibers. Using immunomagnetic purification of GnRH and kisspeptin cells, single-cell nested RT-PCR, and in situ hybridization, we showed that 33% of GnRH neurons and 9–16% of rostral periventricular kisspeptin neurons expressed Gpr147, whereas Gpr74 was not expressed in either population. These data reveal that RFRP-3 can act at two levels of the GnRH neuronal network (i.e. the GnRH neurons and the rostral periventricular kisspeptin neurons) to modulate reproduction but is unable to inhibit gonadotropin secretion independently of GnRH.

scholarly journals Development, Sex Steroid Regulation, and Phenotypic Characterization of RFamide-Related Peptide (Rfrp) Gene Expression and RFamide Receptors in the Mouse Hypothalamus

Endocrinology ◽  
2012 ◽  
Vol 153 (4) ◽  
pp. 1827-1840 ◽  
Author(s):  
Matthew C. Poling ◽  
Joshua Kim ◽  
Sangeeta Dhamija ◽  
Alexander S. Kauffman
Keyword(s):  
In Situ Hybridization ◽  
Estrogen Receptor Α ◽  
Cell Number ◽  
Phenotypic Characterization ◽  
Related Peptide ◽  
Adult Mice ◽  
Gnrh Neurons ◽  
Double Label ◽  
Hormonal Milieu

Arginine-phenylalanine-amide (RFamide)-related peptide 3 (RFRP-3, encoded by the Rfrp gene) is the mammalian ortholog of gonadotropin-inhibiting hormone and can inhibit GnRH neuronal activity and LH release. However, the development and regulation of the RFRP-3 system in both sexes is poorly understood. Using in situ hybridization, we examined changes in Rfrp-expressing neurons in mice of both sexes during development and under different adulthood hormonal milieus. We found no sex differences in Rfrp expression or cell number in adult mice. Interestingly, we identified two interspersed subpopulations of Rfrp cells (high Rfrp-expressing, HE; low Rfrp-expressing, LE), which have unique developmental and steroidal regulation characteristics. The number of LE cells robustly decreases during postnatal development, whereas HE cell number increases significantly before puberty. Using Bax knockout mice, we determined that the dramatic developmental decrease in LE Rfrp cells is not due primarily to BAX-dependent apoptosis. In adults, we found that estradiol and testosterone moderately repress Rfrp expression in both HE and LE cells, whereas the nonaromatizable androgen dihydrotestosterone has no effect. Using double-label in situ hybridization, we determined that approximately 25% of Rfrp neurons coexpress estrogen receptor-α in each sex, whereas Rfrp cells do not readily express androgen receptor in either sex, regardless of hormonal milieu. Lastly, when we looked at RFRP-3 receptors, we detected some coexpression of Gpr147 but no coexpression of Gpr74 in GnRH neurons of both intact and gonadectomized males and females. Thus, RFRP-3 may exert its effects on reproduction either directly, via Gpr147 in a subset of GnRH neurons, and/or indirectly, via upstream regulators of GnRH.

Orchidectomy selectively increases follicle-stimulating hormone secretion in gonadotropin-releasing hormone antagonist-treated male rats

1995 ◽  
Vol 132 (3) ◽  
pp. 357-362 ◽  
Author(s):  
M Tena-Sempere ◽  
L Pinilla ◽  
E Aguilar
Keyword(s):  
Gnrh Antagonist ◽  
Follicle Stimulating Hormone ◽  
Hormone Secretion ◽  
Gonadotropin Releasing Hormone ◽  
Male Rats ◽  
Gonadotropin Secretion ◽  
Releasing Hormone ◽  
Treated Male ◽  
Lh Secretion ◽  
Stimulating Hormone

Tena-Sempere M, Pinilla L, Aguilar E. Orchidectomy selectively increases follicle-stimulating hormone secretion in gonadotropin-releasing hormone agonist-treated male rats. Eur J Endocrinol 1995;132: 357–62. ISSN 0804–4643 The pituitary component of the feedback mechanisms exerted by testicular factors on gonadotropin secretion was analyzed in adult male rats treated with a potent gonadotropin-releasing hormone (GnRH) antagonist. In order to discriminate between androgens and testicular peptides, groups of males were orchidectomized (to eliminate androgens and non-androgenic testicular factors) or injected with ethylene dimethane sulfonate (EDS), a selective toxin for Leydig cells (to eliminate selectively androgens) and treated for 15 days with vehicle or the GnRH antagonist Ac-d-pClPhe-d-pClPhe-d-TrpSer-Tyr-d-Arg-Leu-Arg-Pro-d-Ala-NH2CH3COOH (Org.30276, 5 mg/kg/72 hours). Serum concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured 7 and 14 days after the beginning of treatment. We found that: in males treated with GnRH antagonist, orchidectomy or EDS treatment did not induce any increase in LH secretion; and orchidectomy, but not EDS treatment, increased FSH secretion in GnRH-treated males. The present results show that negative feedback of testicular factors on LH secretion is mediated completely through changes in GnRH actions. In contrast, a part of the inhibitory action of the testis on FSH secretion is exerted directly at the pituitary level. It can be hypothesized that non-Leydig cell testicular factor(s) inputs at different levels of the hypothalamic–pituitary axis in controlling LH and FSH secretion. Manuel Tena-Sempere, Department of Physiology, Faculty of Medicine, University of Córdoba, 14004 Córdoba, Spain

scholarly journals Repetitive Activation of Hypothalamic G Protein-Coupled Receptor 54 with Intravenous Pulses of Kisspeptin in the Juvenile Monkey (Macaca mulatta) Elicits a Sustained Train of Gonadotropin-Releasing Hormone Discharges

Endocrinology ◽  
2006 ◽  
Vol 147 (2) ◽  
pp. 1007-1013 ◽  
Author(s):  
Tony M. Plant ◽  
Suresh Ramaswamy ◽  
Meloni J. DiPietro
Keyword(s):  
G Protein ◽  
Concomitant Treatment ◽  
Secondary Effects ◽  
G Protein Coupled Receptor ◽  
Gnrh Release ◽  
Dependent Signal ◽  
Lh Release ◽  
Lh Secretion ◽  
G Protein Coupled

The purpose of the present study was to further examine the hypothesis that activation of G protein-coupled receptor 54 (GPR54) signaling at the end of the juvenile phase of primate development is responsible for initiation of gonadarche and the onset of puberty. Accordingly, we determined whether repetitive iv administration of the GPR54 receptor agonist kisspeptin-10 (2 μg as a brief 1-min infusion once every hour for 48 h) to the juvenile male rhesus monkey would prematurely elicit sustained, pulsatile release of hypothalamic GnRH, the neuroendocrine trigger for gonadarche. GnRH release was monitored indirectly by measuring LH secretion from the in situ pituitary, the GnRH responsiveness of which had been heightened before the experiment with an intermittent iv infusion of synthetic GnRH. Agonadal animals (n = 4) were employed to eliminate any confounding and secondary effects of changing feedback signals from the testis. The first brief infusion of kisspeptin-10 evoked an LH discharge that mimicked those produced by GnRH priming, and this was followed by a train of similar LH discharges in response to hourly activation of GPR54 by repetitive kisspeptin-10 administration. Concomitant treatment with a GnRH receptor antagonist, acyline, abolished kisspeptin-10-induced LH release. Repetitive kisspeptin-10 administration also provided a GnRH-dependent signal to FSH secretion. These findings are consistent with the notion that, in primates, the transition from the juvenile (attenuated GnRH release) to pubertal (robust GnRH release) state is controlled by activation of GPR54 resulting from increased expression of hypothalamic KiSS-1 and release of kisspeptin in this region of the brain.

Molecular cloning and characterisation of a novel membrane receptor gene from the lobster Jasus edwardsii

2001 ◽  
Vol 204 (19) ◽  
pp. 3369-3377
Author(s):  
Jenny Gaik Imm Khoo ◽  
Frank Y. T. Sin
Keyword(s):  
Signal Transduction ◽  
Signal Sequence ◽  
Receptor Gene ◽  
In Situ Hybridisation ◽  
Phosphorylation Site ◽  
Jasus Edwardsii ◽  
Short Amino Acid Sequence ◽  
Kinase Phosphorylation ◽  
G Protein Coupled

SUMMARY The eyestalk of the lobster, Jasus edwardsii, is an important source for hormones involved in the regulation of growth and reproduction. How these hormones transfer their messages to the cell and nucleus is not known. This paper describes the cloning, characterization and expression analyses of two genes that code for two membrane-associated peptides that may be involved in signal transduction. These genes, peJK2 and peJK3, were isolated from a cDNA library derived from lobster eyestalk mRNAs. The two clones shared 96.6 % sequence homology, and code for putative proteins of 110 and 113 amino acids, respectively. These were likely to be two allelic forms of the same gene. Northern blot analysis using these clones as probes detected the same mRNA from eyestalk, muscle and epithelial extracts, but with greater intensity in the eyestalk extract. In situ hybridisation also indicated the predominant expression of these genes in the eyestalk. Analysis of the putative protein sequences showed that they contained two transmembrane (TM) helices, a short amino acid sequence sharing high homology with the G-protein-coupled receptor (GPCR) motif in the second TM, a signal sequence between the TMs, and a protein kinase phosphorylation site at the C termini. Sequence analyses therefore suggested that the deduced peptides may function in signal transduction.

scholarly journals Changes in RFamide-Related Peptide-1 (RFRP-1)-Immunoreactivity During Postnatal Development and the Estrous Cycle

Endocrinology ◽  
2014 ◽  
Vol 155 (11) ◽  
pp. 4402-4410 ◽  
Author(s):  
Sara R. Jørgensen ◽  
Mille D. Andersen ◽  
Agnete Overgaard ◽  
Jens D. Mikkelsen
Keyword(s):  
Postnatal Development ◽  
Estrous Cycle ◽  
Third Ventricle ◽  
Female Rats ◽  
Male Rats ◽  
Relative Distribution ◽  
Gonadotropin Secretion ◽  
Related Peptide

Abstract GnRH is a key player in the hypothalamic control of gonadotropin secretion from the anterior pituitary gland. It has been shown that the mammalian counterpart of the avian gonadotropin inhibitory hormone named RFamide-related peptide (RFRP) is expressed in hypothalamic neurons that innervate and inhibit GnRH neurons. The RFRP precursor is processed into 2 mature peptides, RFRP-1 and RFRP-3. These are characterized by a conserved C-terminal motif RF-NH2 but display highly different N termini. Even though the 2 peptides are equally potent in vitro, little is known about their relative distribution and their distinct roles in vivo. In this study, we raised an antiserum selective for RFRP-1 and defined the distribution of RFRP-1-immunoreactive (ir) neurons in the rat brain. Next, we analyzed the level of RFRP-1-ir during postnatal development in males and females and investigated changes in RFRP-1-ir during the estrous cycle. RFRP-1-ir neurons were distributed along the third ventricle from the caudal part of the medial anterior hypothalamus throughout the medial tuberal hypothalamus and were localized in, but mostly in between, the dorsomedial hypothalamic, ventromedial hypothalamic, and arcuate nuclei. The number of RFRP-1-ir neurons and the density of cellular immunoreactivity were unchanged from juvenile to adulthood in male rats during the postnatal development. However, both parameters were significantly increased in female rats from peripuberty to adulthood, demonstrating prominent gender difference in the developmental control of RFRP-1 expression. The percentage of c-Fos-positive RFRP-1-ir neurons was significantly higher in diestrus as compared with proestrus and estrus. In conclusion, we found that adult females, as compared with males, have significantly more RFRP-1-ir per cell, and these cells are regulated during the estrous cycle.

Lipopolysaccharide reduces gonadotrophin-releasing hormone (GnRH) gene expression: role of RFamide-related peptide-3 and kisspeptin

2019 ◽  
Vol 31 (6) ◽  
pp. 1134 ◽  
Author(s):  
Chooi Yeng Lee ◽  
ShengYun Li ◽  
Xiao Feng Li ◽  
Daniel A. E. Stalker ◽  
Claire Cooke ◽  
...  
Keyword(s):  
Gene Expression ◽  
In Situ Hybridisation ◽  
Releasing Hormone ◽  
Related Peptide ◽  
Concomitant Reduction ◽  
Intracerebroventricular Injections ◽  
Gonadotrophin Releasing Hormone ◽  
Lh Secretion

RFamide-related peptide (RFRP)-3 reduces luteinising hormone (LH) secretion in rodents. Stress has been shown to upregulate the expression of the RFRP gene (Rfrp) with a concomitant reduction in LH secretion, but an effect on expression of the gonadotrophin-releasing hormone (GnRH) gene (Gnrh1) has not been shown. We hypothesised that lipopolysaccharide (LPS)-induced stress affects expression of Rfrp, the gene for kisspeptin (Kiss1) and/or Gnrh1, leading to suppression of LH levels in rats. Intracerebroventricular injections of RFRP-3 (0.1, 1, 5 nmol) or i.v. LPS (15μgkg−1) reduced LH levels. Doses of 1 and 5 nmol RFRP-3 were then administered to analyse gene expression by in situ hybridisation. RFRP-3 (5 nmol) had no effect on Gnrh1 or Kiss1 expression. LPS stress reduced GnRH and Kiss1 expression, without affecting Rfrp1 expression. These data indicate that LPS stress directly or indirectly reduces Gnrh1 expression, but this is unlikely to be due to a change in Rfrp1 expression.

scholarly journals Interactions between neurotensin and GnRH neurons in the positive feedback control of GnRH/LH secretion in the mouse

2010 ◽  
Vol 298 (1) ◽  
pp. E80-E88 ◽  
Author(s):  
Heather M. Dungan Lemko ◽  
Roxana Naderi ◽  
Valeriya Adjan ◽  
Lothar H. Jennes ◽  
Victor M. Navarro ◽  
...  
Keyword(s):  
Basal Forebrain ◽  
Neural Circuits ◽  
Direct Role ◽  
Lh Surge ◽  
Periventricular Nucleus ◽  
Gnrh Neurons ◽  
Gnrh Release ◽  
Double Label ◽  
Lh Secretion

In female mammals, increased ovarian estradiol (E2) secretion triggers GnRH release from neurons in the basal forebrain, which drives LH secretion from the pituitary and subsequently induces ovulation. However, the neural circuits that activate this preovulatory GnRH/LH surge remain unidentified. Neurotensin is expressed in neurons of the anteroventral periventricular nucleus (AVPV), a region thought to be critical for generating the preovulatory GnRH/LH surge. E2 induces neurotensin ( Nts) gene expression in this region, and blockade of neurotensin signaling reduces the LH surge in the rat. We postulated that neurotensin signaling plays a similar role in generating the E2-induced GnRH/LH surge in mice. We used in situ hybridization (ISH) to determine whether E2 induces Nts expression in the mouse and found evidence to support this proposition. Next, we determined that the neurotensin receptor (Ntsr2) is present in many GnRH-expressing neurons. Since the kisspeptin gene ( Kiss1) is expressed in the AVPV and is responsive to E2, we predicted that some neurons in this region express both Kiss1 and Nts; however, by double-label ISH, we observed no coexpression of the two mRNAs. We also postulated that Nts mRNA expression would increase in parallel with the E2-induced LH surge and that the central (icv) administration of neurotensin would stimulate LH secretion and activation of GnRH neurons but found no evidence to support either of these hypotheses. Together, these findings suggest that, although neurotensin neurons in the AVPV are targets for regulation by E2, neurotensin does not appear to play a direct role in generating the GnRH/LH surge in the mouse.

scholarly journals Regulation of NKB Pathways and Their Roles in the Control of Kiss1 Neurons in the Arcuate Nucleus of the Male Mouse

Endocrinology ◽  
2011 ◽  
Vol 152 (11) ◽  
pp. 4265-4275 ◽  
Author(s):  
V. M. Navarro ◽  
M. L. Gottsch ◽  
M. Wu ◽  
D. García-Galiano ◽  
S. J. Hobbs ◽  
...  
Keyword(s):  
Negative Feedback ◽  
Male Mouse ◽  
Arcuate Nucleus ◽  
Feedback Regulation ◽  
Dynorphin A ◽  
Gonadotropin Secretion ◽  
Negative Feedback Regulation ◽  
Gnrh Neurons ◽  
Kndy Neurons ◽  
Lh Secretion

Kisspeptin (Kiss1) and neurokinin B (NKB) (encoded by the Kiss1 and Tac2 genes, respectively) are indispensable for reproduction. In the female of many species, Kiss1 neurons in the arcuate nucleus (ARC) coexpress dynorphin A and NKB. Such cells have been termed Kiss1/NKB/Dynorphin (KNDy) neurons, which are thought to mediate the negative feedback regulation of GnRH/LH secretion by 17β-estradiol. However, we have less knowledge about the molecular physiology and regulation of Kiss1/Kiss1-expressing neurons in the ARC of the male. Our work focused on the adult male mouse, where we sought evidence for coexpression of these neuropeptides in cells in the ARC, assessed the role of Kiss1 neurons in negative feedback regulation of GnRH/LH secretion by testosterone (T), and investigated the action of NKB on KNDy and GnRH neurons. Results showed that 1) the mRNA encoding Kiss1, NKB, and dynorphin are coexpressed in neurons located in the ARC; 2) Kiss1 and dynorphin A mRNA are regulated by T through estrogen and androgen receptor-dependent pathways; 3) senktide, an agonist for the NKB receptor (neurokinin 3 receptor, encoded by Tacr3), stimulates gonadotropin secretion; 4) KNDy neurons express Tacr3, whereas GnRH neurons do not; and 5) senktide activates KNDy neurons but has no discernable effect on GnRH neurons. These observations corroborate the putative role for KNDy neurons in mediating the negative feedback effects of T on GnRH/LH secretion and provide evidence that NKB released from KNDy neurons is part of an auto-feedback loop that generates the pulsatile secretion of Kiss1 and GnRH in the male.

scholarly journals Effects of Neuron-Specific Estrogen Receptor (ER) α and ERβ Deletion on the Acute Estrogen Negative Feedback Mechanism in Adult Female Mice

Endocrinology ◽  
2014 ◽  
Vol 155 (4) ◽  
pp. 1418-1427 ◽  
Author(s):  
Rachel Y. Cheong ◽  
Robert Porteous ◽  
Pierre Chambon ◽  
István Ábrahám ◽  
Allan E. Herbison
Keyword(s):  
Estrogen Receptor ◽  
Adult Female ◽  
Negative Feedback ◽  
Feedback Mechanism ◽  
Mutant Mice ◽  
Estrous Cycles ◽  
Female Mice ◽  
Negative Feedback Mechanism ◽  
Gnrh Neurons ◽  
Lh Secretion

The negative feedback mechanism through which 17β-estradiol (E2) acts to suppress the activity of the GnRH neurons remains unclear. Using inducible and cell-specific genetic mouse models, we examined the estrogen receptor (ER) isoforms expressed by neurons that mediate acute estrogen negative feedback. Adult female mutant mice in which ERα was deleted from all neurons in the neonatal period failed to exhibit estrous cycles or negative feedback. Adult mutant female mice with neonatal neuronal ERβ deletion exhibited normal estrous cycles, but a failure of E2 to suppress LH secretion was seen in ovariectomized mice. Mutant mice with a GnRH neuron–selective deletion of ERβ exhibited normal cycles and negative feedback, suggesting no critical role for ERβ in GnRH neurons in acute negative feedback. To examine the adult roles of neurons expressing ERα, an inducible tamoxifen-based Cre-LoxP approach was used to ablate ERα from neurons that express calmodulin kinase IIα in adults. This resulted in mice with no estrous cycles, a normal increase in LH after ovariectomy, but an inability of E2 to suppress LH secretion. Finally, acute administration of ERα- and ERβ-selective agonists to adult ovariectomized wild-type mice revealed that activation of ERα suppressed LH secretion, whereas ERβ agonists had no effect. This study highlights the differences in adult reproductive phenotypes that result from neonatal vs adult ablation of ERα in the brain. Together, these experiments expand previous global knockout studies by demonstrating that neurons expressing ERα are essential and probably sufficient for the acute estrogen negative feedback mechanism in female mice.

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