Gonadotrophin and prolactin secretion in castrated male sheep following subcutaneous or intracranial treatment with testicular hormones

Endocrine
D BlacheG B Martin

Abstract

Interactions between testosterone, estradiol, and inhibin in the control of gonadotrophin secretion in males are poorly understood. Castrated rams were treated with steroid-free bovine follicular fluid (bFF), testosterone, or estradiol and for 7 d (2 x 2 x 2 factorial design). Given independently, none of the exogenous hormones affected follicle-stimulating hormone (FSH) concentrations, but the combination of one or both steroids with bFF reduced FSH secretion. Testosterone and estradiol reduced luteinizing hormone (LH) pulse frequency (there was no synergism), and bFF had no effect. Plasma prolactin concentrations were not affected by any treatment. To locate the central sites of steroid action, castrated rams were bilaterally implanted in the preoptic area (POA), ventromedial nucleus (VMH), or arcuate nucleus (ARC). These implants did not affect FSH or prolactin concentrations, or LH pulse amplitude. The frequency of the LH pulses was not affected by testosterone in any site. Estradiol located in the ARC, but not the POA or VMH, decreased LH pulse frequency. In summary, FSH secretion is controlled by synergistic interactions between inhibin and estradiol or testosterone, whereas GnRH/LH pulse frequency is controlled by testic...Continue Reading

References

Apr 1, 1976·Endocrinology·E J KeoghD M De Kretser
Feb 1, 1987·Biology of Reproduction·K E Moore
Feb 1, 1984·Biological Reviews of the Cambridge Philosophical Society·G B Martin
Nov 1, 1984·Journal of Reproduction and Fertility·B D Schanbacher, M J D'Occhio
Sep 1, 1980·Acta Endocrinologica·S P KalraP S Kalra
Jun 1, 1995·Journal of Epidemiology and Community Health·O KrügerS Westin
Jan 1, 1996·Reproduction, Fertility, and Development·S TjondronegoroR Boukhliq

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Citations

Jun 14, 2000·Animal Reproduction Science·C J ScottI J Clarke
Mar 3, 2005·Reproduction, Fertility, and Development·T P SharmaG B Martin
Jul 25, 2008·Reproduction in Domestic Animals = Zuchthygiene·D BlacheS K Maloney
Nov 8, 2018·The Journal of Endocrinology·Christopher J ScottBriony M McGrath
Sep 13, 2019·Reproduction, Fertility, and Development·S E RietemaJ T Smith

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