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Titolo:
In vitro effect of leptin on LH release by anterior pituitary glands from female rats at the time of spontaneous and steroid-induced LH surge
Autore:
De Biasi, SN; Apfelbaum, LI; Apfelbaum, ME;
Indirizzi:
Univ Nacl Cordoba, Dept Bioquim Clin, Fac Ciencias Quim, RA-5000 Cordoba, Argentina Univ Nacl Cordoba Cordoba Argentina RA-5000 , RA-5000 Cordoba, Argentina
Titolo Testata:
EUROPEAN JOURNAL OF ENDOCRINOLOGY
fascicolo: 5, volume: 145, anno: 2001,
pagine: 659 - 665
SICI:
0804-4643(200111)145:5<659:IVEOLO>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
NITRIC-OXIDE SYNTHASE; IN-VITRO; NEUROENDOCRINE REGULATION; GENE-EXPRESSION; OBESE GENE; ADULT-RAT; HORMONE; SECRETION; RECEPTOR; HYPOTHALAMUS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Apfelbaum, ME Univ Nacl Cordoba, Dept Bioquim Clin, Fac Ciencias Quim, Agencia Postal 4,Casilla de Correo 61, RA-5000 Cordoba, Argentina Univ Nacl Cordoba Agencia Postal 4,Casilla de Correo 61 Cordoba Argentina RA-5000
Citazione:
S.N. De Biasi et al., "In vitro effect of leptin on LH release by anterior pituitary glands from female rats at the time of spontaneous and steroid-induced LH surge", EUR J ENDOC, 145(5), 2001, pp. 659-665

Abstract

Objective: The purpose of this work was to study the direct effect of leptin on LH release by anterior pituitary glands from female rats at the time of spontaneous and steroid-induced LK surge. Methods: LH responsiveness to leptin by pituitaries from rats killed in the afternoon (1500 h) at different stages of the 4-day estrous cycle (diestrus-1: DI; diestrus-2: D2; proestrus; estrus), ovariectomized (OVX; 15 days post-castration) and ovariectomized steroid-primed (OVX-E-2/Pg; pretreated with 5 mug estradiol and I mg progesterone), was evaluated in vitro. Hemi-adenohypophyses were incubated in the presence of synthetic murine leptin for 3 h. Results: Addition of increasing concentrations of leptin (0.1-100 nmol/l) to the incubation medium of proestrus pituitaries produced a dose-related stimulation of LH release; the maximal increase to 315% of control was obtained with 10 nmol/l leptin. Leptin (10 nmol/l) enhanced LH release at all days of the estrous cycle, the greatest response occurring in proestrus (318%) and the lowest at D1 (123%). In order to evaluate the role of nitric oxide (NO) in the action of leptin on LH release, glands from proestrus rats were incubated in the presence of 10 nmol/l leptin with or without 0.3 mmol/lN-G-monomethyl-L-arginine (NMMA), a competitive inhibitor of NO synthase (NOS). NMMA completely suppressed the stimulation of LH release induced by leptin. Leptin also stimulated LH release by pituitaries from OVX rats, and treatment with steroid hormones led to a marked increase in the response (OVX: 162% compared with OVX-E-2/Pg: 263%; P < 0.05). For comparative analysis, a similar experimental procedure was carried out using GnRH (10 nmol/l). Leptin acts at the pituitary level in a similar manner as GnRH, although with significantly lower potency. Conclusions: These results confirm and extend previous reports regarding adirect action of leptin at the pituitary level, stimulating LH release by anterior pituitaries from female rats at the time of spontaneous and steroid-induced LH surge. In the female rat pituitary this leptin action is controlled by gonadal steroids and mediated by NO.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/01/20 alle ore 10:21:22