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Science 30 May 1980:
Vol. 208. no. 4447, pp. 1037 - 1039
DOI: 10.1126/science.6990489
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Articles

Science, Vol 208, Issue 4447, 1037-1039
Copyright © 1980 by American Association for the Advancement of Science

articles

Progesterone administration in vivo stimulates release of luteinizing hormone-releasing hormone in vitro

VD Ramirez, D Dluzen, and D Lin

The release of luteinizing hormone-releasing hormone (LHRH) from tissue from the mediobasal hypothalamic-anterior hypothalamic-preoptic area of prepuberal female rats was measured in a perfusion system. Measurements were also made of the concentrations of LHRH in these tissue fragments and of luteinizing hormone in serum obtained when the rats were killed. Four groups of immature rats were studied: intact, ovariectomized, ovariectomized and implanted with estradiol-containing capsules, and ovariectomized rats primed with estradiol and injected with progesterone. The release of LHRH from the tissue of ovariectomized animals was significantly less than that of intact females and was not modified when the ovariectomized rats received estradiol. However, there was a four- to fivefold increase in LHRH release from tissue of ovariectomized rats primed with estradiol when they were killed 6 hours after they received an injection of progesterone. The concentrations of LHRH in tissue and of luteinizing hormone in serum varied among groups and with the time of day that the animals were killed. The interactions among luteinizing hormone, gonadal steroids, and the photoperiod seem to set the appropriate conditions for neural processes triggering a complete and normal release of luteinizing hormone.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Progesterone Priming Is Essential for the Full Expression of the Positive Feedback Effect of Estradiol in Inducing the Preovulatory Gonadotropin-Releasing Hormone Surge in the Ewe.
A. Caraty and D. C. Skinner (1999)
Endocrinology 140, 165-170
   Abstract »    Full Text »
Tonic Support of Luteinizing Hormone Secretion by Adrenal Progesterone in the Ovariectomized Monkey Replaced with Midfollicular Phase Levels of Estradiol.
E. Xiao, L. Xia-Zhang, D. Shanen, and M. Ferin (1997)
J. Clin. Endocrinol. Metab. 82, 2233-2238
   Abstract »    Full Text »    PDF »


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