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Titolo:
NEUROENDOCRINE CONTROL OF FOLLICLE-STIMULATING-HORMONE (FSH) SECRETION .1. DIRECT EVIDENCE FOR SEPARATE EPISODIC AND BASAL COMPONENTS OF FSH-SECRETION
Autore:
PADMANABHAN V; MCFADDEN K; MAUGER DT; KARSCH FJ; MIDGLEY R;
Indirizzi:
UNIV MICHIGAN,REPROD SCI PROGRAM,300 N INGALLS BLDG,ROOM 1101 ANN ARBOR MI 48109 UNIV MICHIGAN,DEPT PEDIAT ANN ARBOR MI 48109 UNIV MICHIGAN,DEPT PHYSIOL ANN ARBOR MI 48109 UNIV MICHIGAN,DEPT BIOSTAT ANN ARBOR MI 48109
Titolo Testata:
Endocrinology
fascicolo: 1, volume: 138, anno: 1997,
pagine: 424 - 432
SICI:
0013-7227(1997)138:1<424:NCOF(S>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
GONADOTROPIN-RELEASING-HORMONE; MESSENGER-RIBONUCLEIC-ACID; ALPHA-SUBUNIT SECRETION; RAT PITUITARY-CELLS; LUTEINIZING-HORMONE; PULSE FREQUENCY; METABOLIC-CLEARANCE; NUTRITIONAL REPLETION; OVARIECTOMIZED EWES; GNRH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
60
Recensione:
Indirizzi per estratti:
Citazione:
V. Padmanabhan et al., "NEUROENDOCRINE CONTROL OF FOLLICLE-STIMULATING-HORMONE (FSH) SECRETION .1. DIRECT EVIDENCE FOR SEPARATE EPISODIC AND BASAL COMPONENTS OF FSH-SECRETION", Endocrinology, 138(1), 1997, pp. 424-432

Abstract

Continuous sampling of hypophyseal portal blood from unrestrained sheep is providing an unprecedented means for measuring and defining the characteristics of the secretory profile of GnRH. With this method, GnRH has been shown to be released in discrete pulses lasting 5-8 min, with the amplitude of some pulses exceeding 50-fold. Although the relationship between these pulses and the accompanying pulses of LH measured in the jugular vein are unambiguous, the relationship of GnRH pulsesto the release of FSH has not been well defined due to the longer clearance of FSH. In previous studies we have shown that hypophyscal portal blood, in addition to serving as a source material for hypothalamicsecretions, provides a means to define secretory patterns of pituitary hormones. Because of this we hypothesized that the GnRH-FSH secretory relationships would be easier to define in hypophyseal portal than in jugular vein blood before the secretory products are subjected to dispersion and clearance in circulation. To test this possibility, we monitored hormonal patterns in blood collected at 5-min intervals for 6-12 h from the peripheral and hypophyseal portal circulation of six ovariectomized ewes from a previous study. In contrast to the nonpulsatile pattern of FSH in the peripheral blood, 93% of GnRH pulses were associated with essentially coincident, discrete pulses of FSH in the portal plasma. Of potentially even greater interest, additional episodes of FSH release were clearly discernible between the GnRH-associated pulses of FSH. As concentrations of peripheral plasma FSH did not reach those in hypophyseal portal plasma, the inter-GnRH episodes of FSH secretion could not result from contaminating peripheral blood. In addition to the episodic mode of secretion, substantial amounts of FSH were found between FSH pulses. This basal component of FSH appeared to be the dominant mode of secretion rather than pulses. The results of this study not only confirm that GnRH pulses lead to pulsatile release of FSH, they also suggest that some other mechanism or factor may be controlling the non-GnRH-associated episodes as well as the basal componentsof FSH secretion.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 21:40:52