Luteinising Hormone Secretion from the Perif used Ovine Pars tuberalis and Pars distalis: Effects of Gonadotropin-Releasing Hormone and Melatonin

1997 ◽  
Vol 66 (4) ◽  
pp. 263-270 ◽  
Author(s):  
Donal C. Skinner ◽  
Jane E. Robinson
Keyword(s):  
Luteinising Hormone ◽  
Hormone Secretion ◽  
Gonadotropin Releasing Hormone ◽  
Pars Tuberalis ◽  
Pars Distalis ◽  
Releasing Hormone

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

Regulation of Gonadotropin-Releasing Hormone and Luteinizing Hormone Secretion by AMPA Receptors

1997 ◽  
Vol 66 (4) ◽  
pp. 246-253 ◽  
Author(s):  
Lin Ping ◽  
Virendra B. Mahesh ◽  
Ganapathy K. Bhat ◽  
Darrell W. Brann
Keyword(s):  
Luteinizing Hormone ◽  
Ampa Receptors ◽  
Hormone Secretion ◽  
Gonadotropin Releasing Hormone ◽  
Luteinizing Hormone Secretion ◽  
Releasing Hormone

scholarly journals Neuropeptide Y mediates orexin A-mediated suppression of pulsatile gonadotropin-releasing hormone secretion in ovariectomized rats

2011 ◽  
Vol 58 (1,2) ◽  
pp. 11-18 ◽  
Author(s):  
Machiko Kiyokawa ◽  
Toshiya Matsuzaki ◽  
Takeshi Iwasa ◽  
Rie Ogata ◽  
Masahiro Murakami ◽  
...  
Keyword(s):  
Neuropeptide Y ◽  
Hormone Secretion ◽  
Gonadotropin Releasing Hormone ◽  
Ovariectomized Rats ◽  
Orexin A ◽  
Releasing Hormone

scholarly journals Induction of final oocyte maturation in Cyprinidae fish by hypothalamic factors: a review

2009 ◽  
Vol 54 (No. 3) ◽  
pp. 97-110 ◽  
Author(s):  
P. Podhorec ◽  
J. Kouril
Keyword(s):  
Luteinizing Hormone ◽  
Oocyte Maturation ◽  
Hormone Secretion ◽  
Inhibitory Effect ◽  
Gonadotropin Releasing Hormone ◽  
Luteinizing Hormone Secretion ◽  
Releasing Hormone ◽  
Final Oocyte Maturation ◽  
In Captivity ◽  
Lh Secretion

Gonadotropin-releasing hormone in Cyprinidae as in other Vertebrates functions as a brain signal which stimulates the secretion of luteinizing hormone from the pituitary gland. Two forms of gonadotropin-releasing hormone have been identified in cyprinids, chicken gonadotropin-releasing hormone II and salmon gonadotropin-releasing hormone. Hypohysiotropic functions are fulfilled mainly by salmon gonadotropin-releasing hormone. The only known factor having an inhibitory effect on LH secretion in the family Cyprinidae is dopamine. Most cyprinids reared under controlled conditions exhibit signs of reproductive dysfunction, which is manifested in the failure to undergo final oocyte maturation and ovulation. In captivity a disruption of endogenous gonadotropin-releasing hormone stimulation occurs and sequentially that of luteinizing hormone, which is indispensible for the final phases of gametogenesis. In addition to methods based on the application of exogenous gonadotropins, the usage of a method functioning on the basis of hypothalamic control of final oocyte maturation and ovulation has become popular recently. The replacement of natural gonadotropin-releasing hormones with chemically synthesized gonadotropin-releasing hormone analogues characterized by amino acid substitutions at positions sensitive to enzymatic degradation has resulted in a centuple increase in the effectiveness of luteinizing hormone secretion induction. Combining gonadotropin-releasing hormone analogues with Dopamine inhibitory factors have made it possible to develop an extremely effective agent, which is necessary for the successful artificial reproduction of cyprinids.

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