Importance of the gonadotropin-releasing hormone (GnRH) surge for induction of the preovulatory luteinizing hormone surge of the ewe: dose-response relationship and excess of GnRH

Endocrinology
J M BowenF J Karsch

Abstract

The preovulatory LH surge in the ewe is stimulated by a large sustained surge of GnRH. We have previously demonstrated that the duration of this GnRH signal exceeds that necessary to initiate and sustain the LH surge. The objective of the present study was to determine whether a similar excess exists for amplitude of the GnRH surge. Experiments were performed using an animal model in which GnRH secretion was blocked by progesterone, which in itself does not block the pituitary response to GnRH. To assess the amplitude of the GnRH surge needed to induce the LH surge, we introduced artificial GnRH surges of normal contour and duration but varying amplitudes. Twelve ewes were run through 3 successive artificial follicular phases (total of 36). Six of these artificial follicular phases were positive controls, in which progesterone was removed, the estradiol stimulus was provided, and vehicle was infused. In these control cycles, animals generated endogenous LH surges. In the remaining artificial follicular phases, progesterone was not withdrawn, the estradiol stimulus was provided, and either vehicle (negative control) or GnRH solutions of varying concentrations (experimental) were infused. The circulating GnRH concentrations achie...Continue Reading

References

Dec 2, 1976·Nature·D K SarkarN M Sherwood
Jun 1, 1992·Biology of Reproduction·J Ishikawa
Sep 1, 1990·Endocrinology·S M MoenterF J Karsch
Jun 1, 1987·Neuroendocrinology·I J ClarkeJ T Cummins
Jun 1, 1972·Computers and Biomedical Research, an International Journal·W G DuddlesonG D Niswender
May 1, 1969·Endocrinology·G D NiswenderA V Nalbandov
Jul 1, 1980·The Journal of Clinical Endocrinology and Metabolism·W F Crowley, J W McArthur
Dec 1, 1981·Pharmacology, Biochemistry, and Behavior·J E ZadinaD H Coy
Jul 19, 1994·Proceedings of the National Academy of Sciences of the United States of America·J E HallW F Crowley
Feb 1, 1997·Biology of Reproduction·F J KarschS M Moenter

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Citations

Dec 6, 2008·Biology of Reproduction·Elizabeth R WagenmakerFred J Karsch
Apr 22, 2003·American Journal of Human Biology : the Official Journal of the Human Biology Council·Deborah K Barnett, David H Abbott
Jul 22, 2016·Reproduction, Fertility, and Development·K D SinclairC M Dwyer

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