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Titolo:
GONADOTROPIN-RELEASING-HORMONE REQUIREMENTS FOR OVULATION
Autore:
KARSCH FJ; BOWEN JM; CARATY A; EVANS NP; MOENTER SM;
Indirizzi:
UNIV MICHIGAN,REPROD SCI PROGRAM,300 N INGALLS ANN ARBOR MI 48109 UNIV MICHIGAN,DEPT PHYSIOL ANN ARBOR MI 48109 INRA,PHYSIOL REPROD STN F-37380 NOUZILLY FRANCE
Titolo Testata:
Biology of reproduction
fascicolo: 2, volume: 56, anno: 1997,
pagine: 303 - 309
SICI:
0006-3363(1997)56:2<303:GRFO>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
PREOVULATORY GNRH SURGE; PITUITARY-STALK PLASMA; OVINE ESTROUS-CYCLE; LUTEINIZING-HORMONE; OVARIECTOMIZED EWES; RHESUS-MONKEY; PERIOVULATORY PERIOD; FEEDBACK ACTIONS; ANESTROUS EWES; SECRETION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
62
Recensione:
Indirizzi per estratti:
Citazione:
F.J. Karsch et al., "GONADOTROPIN-RELEASING-HORMONE REQUIREMENTS FOR OVULATION", Biology of reproduction, 56(2), 1997, pp. 303-309

Abstract

This article addresses the role of GnRH in ovulation in the context of two general models of GnRH action-deterministic and permissive. According to the deterministic model, increased GnRH secretion is requiredto induce the preovulatory LH surge and thus ovulation. The permissive model, in contrast, holds that GnRH secretion need not increase. Rather, the preovulatory LH surge results from enhanced sensitivity of the pituitary gland to GnRH. Studies in rodents and rabbits support the deterministic model whereas evidence in primates suggests that GnRH ispermissive. Three lines of evidence are presented to support the conclusion that GnRH plays a deterministic role in sheep. First, a large GnRH surge is secreted together with the preovulatory LH surge. Second,the follicular phase increase in circulating estradiol concentration stimulates this GnRH surge by a positive feedback effect. Third, initiation of the LH surge requires an abrupt increase in GnRH, and maintenance of the LH surge requires continued GnRH support. Collectively, these observations document the fundamental importance of a GnRH surge to ovulation and generation of the estrous cycle of sheep.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 07:43:39