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Titolo:
FOS EXPRESSION DURING THE ESTRADIOL-INDUCED GONADOTROPIN-RELEASING-HORMONE (GNRH) SURGE OF THE EWE - INDUCTION IN GNRH AND OTHER NEURONS
Autore:
MOENTER SM; KARSCH FJ; LEHMAN MN;
Indirizzi:
UNIV CALIF SAN FRANCISCO,COLL MED,DEPT OBSTET & GYNECOL,CTR REPROD ENDOCRINOL,BOX 0556 SAN FRANCISCO CA 94143 UNIV MICHIGAN,REPROD SCI PROGRAM ANN ARBOR MI 48109 UNIV MICHIGAN,DEPT PHYSIOL ANN ARBOR MI 48109 UNIV CINCINNATI,COLL MED,DEPT ANAT & CELL BIOL CINCINNATI OH 45267
Titolo Testata:
Endocrinology
fascicolo: 2, volume: 133, anno: 1993,
pagine: 896 - 903
SICI:
0013-7227(1993)133:2<896:FEDTEG>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
LUTEINIZING-HORMONE; ESTROUS-CYCLE; C-FOS; LH-SECRETION; SHEEP; PROGESTERONE; RAT; IMMUNOREACTIVITY; HYPOTHALAMUS; LOCALIZATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
37
Recensione:
Indirizzi per estratti:
Citazione:
S.M. Moenter et al., "FOS EXPRESSION DURING THE ESTRADIOL-INDUCED GONADOTROPIN-RELEASING-HORMONE (GNRH) SURGE OF THE EWE - INDUCTION IN GNRH AND OTHER NEURONS", Endocrinology, 133(2), 1993, pp. 896-903

Abstract

The protein product of the protooncogene c-fos was used as a marker of cellular activation in an attempt to identify those neurons in the preoptic area and hypothalamus that participate in generation of the estradiol-induced surge of GnRH in the ewe. GnRH- and Fos-expressing cells were identified immunocytochemically, and the percent of coexpression was determined in three states: mid-luteal phase (low GnRH release,n = 6); short-term ovariectomy (high episodic GnRH release, n = 6); and induced GnRH surge (high sustained release, n = 8). To induce the GnRH surge, a follicular phase rise in circulating estradiol was simulated in a physiological model for the estrous cycle. Serum LH was measured as an indicator of GnRH release. In the luteal phase, LH was basal, indicating low GnRH secretion. Few cells expressed Fos; these were not GnRH cells. Despite high intermittent GnRH release in short-term ovariectomized ewes, GnRH cells did not express Fos. During the surge (sustained high GnRH release), 41 +/- 8% of GnRH cells expressed Fos; these cells were dispersed throughout the field of distribution of GnRH neurons. In addition to Fos in GnRH-positive cells, many more non-GnRHcells in the preoptic area, anterior hypothalamus, and ventrolateral hypothalamus expressed Fos during the surge than in the luteal phase or after ovariectomy. We suggest that Fos expression in GnRH cells is markedly increased by the positive feedback action of estradiol (surge), whereas short-term removal of negative feedback (ovariectomy) has little, if any, effect, despite increased GnRH release in both states. Since estradiol induces Fos expression in far more than GnRH neurons, our results also suggest that estradiol activates other cells, some of which may be part of a neuronal chain leading to GnRH surge generation, and some of which may be related to other neural actions of estradiol, such as estrous behavior.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/11/20 alle ore 14:09:48