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Titolo:
THE PREOVULATORY GONADOTROPIN-RELEASING-HORMONE SURGE - A NEUROENDOCRINE SIGNAL FOR OVULATION
Autore:
CARATY A; EVANS NP; FABRENYS CJ; KARSCH FJ;
Indirizzi:
INRA,PHYSIOL REPROD MAMMIFERES DOMEST STN F-37380 NOUZILLY FRANCE UNIV MICHIGAN,DEPT PHYSIOL ANN ARBOR MI 48109 UNIV MICHIGAN,REPROD SCI PROGRAM ANN ARBOR MI 48109
Titolo Testata:
Journal of Reproduction and Fertility
, , anno: 1995, supplemento:, 49
pagine: 245 - 255
SICI:
0022-4251(1995):<245:TPGS-A>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
PULSE-GENERATOR ACTIVITY; LUTEINIZING-HORMONE; OVARIECTOMIZED EWES; GNRH SECRETION; RHESUS-MONKEY; IMMUNOREACTIVE NEURONS; PERIOVULATORY PERIOD; MEDIAN-EMINENCE; MENSTRUAL-CYCLE; ANESTROUS EWES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
50
Recensione:
Indirizzi per estratti:
Citazione:
A. Caraty et al., "THE PREOVULATORY GONADOTROPIN-RELEASING-HORMONE SURGE - A NEUROENDOCRINE SIGNAL FOR OVULATION", Journal of Reproduction and Fertility, 1995, pp. 245-255

Abstract

Recent studies have demonstrated that an important component of the positive feedback response to oestradiol in mammals is an action withinthe central nervous system to induce a large surge in the secretion of gonadotrophin-releasing hormone (GnRH). This oestradiol-induced neuroendocrine signal for ovulation has been best characterized in ewes. The GnRH surge is high in amplitude; the amount secreted increases on average more than 40 times above the pre-surge baseline value. The initial increment in GnRH secretion precedes or coincides with the onset of the LH surge. The GnRH surge is of extended duration, lasting far longer than the preovulatory LH surge. A molecular variant of GnRH, which is less active biologically than native GnRH, is co-secreted at the time of the surge, but termination of the LH surge cannot be accountedfor by a change in biological activity of the secreted GnRH. Generation of the GnRH surge appears to follow a characteristic progressive change in the pattern of GnRH in portal blood. High concentrations of oestradiol initially stimulate the secretion of GnRH between pulses; this is followed by augmentation of both pulsatile and interpulse GnRH release producing the rising limb of the surge. Finally, recent experiments have indicated that the local application of oestradiol to the ventromedial nucleus of the hypothalamus is sufficient to stimulate the GnRH surge, suggesting a key role for this hypothalamic area in the generation of this neuroendocrine signal for ovulation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 07:13:14