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Titolo:
DOES ESTRADIOL INDUCE THE PREOVULATORY GONADOTROPIN-RELEASING-HORMONE(GNRH) SURGE IN THE EWE BY INDUCING A PROGRESSIVE CHANGE IN THE MODE OF OPERATION OF THE GNRH NEUROSECRETORY-SYSTEM
Autore:
EVANS NP; DAHL GE; MAUGER DT; PADMANABHAN V; THRUN LA; KARSCH FJ;
Indirizzi:
UNIV MICHIGAN,REPROD SCI PROGRAM,300 N INGALLS BLDG,ROOM 1101 SW ANN ARBOR MI 48109 UNIV MICHIGAN,REPROD SCI PROGRAM ANN ARBOR MI 48109 UNIV MICHIGAN,DEPT PHYSIOL ANN ARBOR MI 48109 UNIV MICHIGAN,DEPT BIOL ANN ARBOR MI 48109 UNIV MICHIGAN,DEPT PEDIAT ANN ARBOR MI 48109 UNIV MICHIGAN,DEPT BIOSTAT ANN ARBOR MI 48109
Titolo Testata:
Endocrinology
fascicolo: 12, volume: 136, anno: 1995,
pagine: 5511 - 5519
SICI:
0013-7227(1995)136:12<5511:DEITPG>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
PULSE-GENERATOR ACTIVITY; LUTEINIZING-HORMONE; OVARIECTOMIZED EWES; RHESUS-MONKEY; MEDIAN-EMINENCE; PITUITARY-GLAND; ESTROUS-CYCLE; LH-SECRETION; HYPOTHALAMUS; PATTERN;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
55
Recensione:
Indirizzi per estratti:
Citazione:
N.P. Evans et al., "DOES ESTRADIOL INDUCE THE PREOVULATORY GONADOTROPIN-RELEASING-HORMONE(GNRH) SURGE IN THE EWE BY INDUCING A PROGRESSIVE CHANGE IN THE MODE OF OPERATION OF THE GNRH NEUROSECRETORY-SYSTEM", Endocrinology, 136(12), 1995, pp. 5511-5519

Abstract

Estradiol profoundly influences GnRH secretion during the follicular phase of the estrous cycle of the sheep. Estradiol not only regulates the frequency and amplitude of GnRH pulses, but also produces qualitative changes in its pattern of release and induces a sustained GnRH surge during which discrete pulses are not readily evident. In this study, we tested the hypothesis that qualitative changes in GnRH secretion are an integral part of an estradiol-induced change in the mode of operation of the GnRH neurosecretory system that leads to generation of the GnRH surge. This was achieved by the measurement of GnRH in samplesof pituitary portal blood collected at 1-min intervals for an 11-h period encompassing the pre- and early surge periods in an artificial follicular phase model. In each of the seven ewes studied, a highly characteristic alteration in the moment to moment pattern of GnRH was observed. This consisted of a progressive change from a strictly episodic pattern of GnRH release to one containing both episodic and nonepisodic components and, after amplification of both components, a period of extremely high values during which individual episodic increases were no longer readily recognizable. Preliminary mathematical modeling of the data suggested that these patterns could be produced by a change inGnRH from a predominantly low to a mixture of low and high amplitude inputs. Similar changes in minute to minute patterns of GnRH secretionwere observed during the natural follicular phase. These findings areconsistent with the hypothesis that estradiol induces the GnRH surge by altering the mode of neurosecretion, rather than by merely causing quantitative changes in the episodic pattern of release.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/11/20 alle ore 21:50:41