N-methyl-D,L-aspartate (NMDA) stimulates gonadotropin secretion in the ovine fetus through gonadotropin-releasing hormone (GnRH) release

1988 ◽  
Vol 117 (4_Suppl) ◽  
pp. S93-S94
Author(s):  
M. BETTENDORF ◽  
F. DE ZEGHER ◽  
N. ALBERS ◽  
S. L. KAPLAN ◽  
M. M. GRUMBACH
Keyword(s):  
Gonadotropin Releasing Hormone ◽  
Gonadotropin Secretion ◽  
Releasing Hormone ◽  
Gnrh Release ◽  
Ovine Fetus

Neuroanatomical Organization of the Brain Gonadotropin-Inhibitory Hormone and Gonadotropin-Releasing Hormone Systems in the Frog Pelophylax esculentus

2014 ◽  
Vol 85 (1) ◽  
pp. 15-28 ◽  
Author(s):  
Claudia Pinelli ◽  
Arun G. Jadhao ◽  
Saikat P. Biswas ◽  
Kazuyoshi Tsutsui ◽  
Biagio D''Aniello
Keyword(s):  
Preoptic Area ◽  
Anterior Commissure ◽  
Medial Septum ◽  
Gonadotropin Releasing Hormone ◽  
Gonadotropin Secretion ◽  
Releasing Hormone ◽  
Gnrh Release ◽  
Medial Septal Area ◽  
Gonadotropin Inhibitory Hormone ◽  
The Brain

Growing evidence suggests that gonadotropin-inhibitory hormone (GnIH) may play a key role in mediating vertebrate reproduction. GnIH inhibits gonadotropin synthesis and release by decreasing the activity of gonadotropin-releasing hormone (GnRH) neurons as well as by directly regulating gonadotropin secretion from the pituitary. Whereas the presence of GnIH has been widely investigated in various classes of vertebrates, there are very few immunohistochemical reports focusing on GnIH in amphibians. The aim of this study was to assess the presence and neuroanatomical distribution of GnIH-like immunoreactivity in the brain of the anuran amphibian Pelophylax (Rana) esculentus (esculenta) and to explore any potential anatomical relationship with mammalian GnRH-immunoreactive (mGnRH-ir) elements. The GnIH-like immunoreactive (GnIH-ir) system constitutes two distinct subpopulations in the telencephalon and diencephalon, with the highest number of immunoreactive cells located in the preoptic and suprachiasmatic areas. GnIH-ir neurons were also observed in the medial septum, the anterior commissure, the dorsal hypothalamus, the periventricular nucleus of the hypothalamus, and the posterior tuberculum. Scattered GnIH-ir fibers were present in all major subdivisions of the brain but only occasionally in the median eminence. mGnRH-ir neurons were distributed in the mediobasal telencephalon, the medial septal area, and the anterior preoptic area. Double-label immunohistochemistry revealed that the GnRH and GnIH systems coexist and have overlapping distributions at the level of the anterior preoptic area. Some GnIH-ir fibers were in close proximity to mGnRH-ir cell bodies. Our results suggest that both the neuroanatomy and the functional regulation of GnRH release are conserved properties of the hypothalamic GnIH-ir system among vertebrate species.

scholarly journals Distinct Mechanisms Involving Diverse Histone Deacetylases Repress Expression of the Two Gonadotropin β-Subunit Genes in Immature Gonadotropes, and Their Actions Are Overcome by Gonadotropin-Releasing Hormone

2007 ◽  
Vol 27 (11) ◽  
pp. 4105-4120 ◽  
Author(s):  
Stefan Lim ◽  
Min Luo ◽  
Mingshi Koh ◽  
Meng Yang ◽  
Mohammed Nizam bin Abdul Kadir ◽  
...  
Keyword(s):  
Histone Deacetylases ◽  
Reproductive Function ◽  
Gonadotropin Releasing Hormone ◽  
Β Subunit ◽  
Releasing Hormone ◽  
Calcium Calmodulin Dependent ◽  
Gnrh Release ◽  
Dependent Protein ◽  
Reproductive Cycles ◽  
Class Iia Hdacs

ABSTRACT The gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are produced in the embryonic pituitary in response to delivery of the hypothalamic gonadotropin releasing hormone (GnRH). GnRH has a pivotal role in reestablishing gonadotropin levels at puberty in primates, and for many species with extended reproductive cycles, these are reinitiated in response to central nervous system-induced GnRH release. Thus, a clear role is evident for GnRH in overcoming repression of these genes. Although the mechanisms through which GnRH actively stimulates LH and FSH β-subunit (FSHβ) gene transcription have been described in some detail, there is currently no information on how GnRH overcomes repression in order to terminate reproductively inactive stages. We show here that GnRH overcomes histone deacetylase (HDAC)-mediated repression of the gonadotropin β-subunit genes in immature gonadotropes. The repressive factors associated with each of these genes comprise distinct sets of HDACs and corepressors which allow for differentially regulated derepression of these two genes, produced in the same cell by the same regulatory hormone. We find that GnRH activation of calcium/calmodulin-dependent protein kinase I (CaMKI) plays a crucial role in the derepression of the FSHβ gene involving phosphorylation of several class IIa HDACs associated with both the FSHβ and Nur77 genes, and we propose a model for the mechanisms involved. In contrast, derepression of the LH β-subunit gene is not CaMK dependent. This demonstration of HDAC-mediated repression of these genes could explain the temporal shut-down of reproductive function at certain periods of the life cycle, which can easily be reversed by the actions of the hypothalamic regulatory hormone.

scholarly journals Effects of Sex Steroid Treatments on Gonadotropin-Releasing Hormone-Stimulated Gonadotropin Secretion from the Goldfish Pituitary1

1993 ◽  
Vol 48 (2) ◽  
pp. 300-307 ◽  
Author(s):  
V. L. Trudeau ◽  
C. K. Murthy ◽  
H. R. Habibi ◽  
B. D. Sloley ◽  
R. E. Peter
Keyword(s):  
Gonadotropin Releasing Hormone ◽  
Sex Steroid ◽  
Gonadotropin Secretion ◽  
Releasing Hormone

scholarly journals Sexual Differentiation of the Surge Mode of Gonadotropin Secretion: Prenatal Androgens Abolish the Gonadotropin-Releasing Hormone Surge in the Sheep

1996 ◽  
Vol 8 (8) ◽  
pp. 627-633 ◽  
Author(s):  
Cristina G. Herbosa ◽  
Geoffrey E. Dahl ◽  
Neil P. Evans ◽  
Juanita Pelt ◽  
Ruth I. Wood ◽  
...  
Keyword(s):  
Sexual Differentiation ◽  
Gonadotropin Releasing Hormone ◽  
Gonadotropin Secretion ◽  
Releasing Hormone ◽  
Prenatal Androgens

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

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