Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Oestradiol microimplants in the ventromedial preoptic area inhibit secretion of luteinizing hormone via dopamine neurones in anoestrous ewes
Autore:
Anderson, GM; Connors, JM; Hardy, SL; Valent, M; Goodman, RL;
Indirizzi:
W Virginia Univ, Hlth Sci Ctr N, Dept Physiol, Morgantown, WV 26506 USA W Virginia Univ Morgantown WV USA 26506 Physiol, Morgantown, WV 26506 USA
Titolo Testata:
JOURNAL OF NEUROENDOCRINOLOGY
fascicolo: 12, volume: 13, anno: 2001,
pagine: 1051 - 1058
SICI:
0953-8194(200112)13:12<1051:OMITVP>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
GONADOTROPIN-RELEASING-HORMONE; PULSATILE LH-SECRETION; RECEPTOR-IMMUNOREACTIVE CELLS; ESTRADIOL NEGATIVE FEEDBACK; MESSENGER-RIBONUCLEIC-ACID; ESTROGEN-RECEPTOR; TYROSINE-HYDROXYLASE; BETA-ENDORPHIN; PROLACTIN SECRETION; SEASONAL-CHANGES;
Keywords:
seasonal reproduction; oestradiol; dopamine; preoptic area; hypothalamus;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Goodman, RL W Virginia Univ, Hlth Sci Ctr N, Dept Physiol, Med Ctr Dr, Morgantown, WV 26506 USA W Virginia Univ Med Ctr Dr Morgantown WV USA 26506 V 26506 USA
Citazione:
G.M. Anderson et al., "Oestradiol microimplants in the ventromedial preoptic area inhibit secretion of luteinizing hormone via dopamine neurones in anoestrous ewes", J NEUROENDO, 13(12), 2001, pp. 1051-1058

Abstract

Oestradiol exerts a season-specific negative feedback effect on the GnRH/LH neurosecretory system of the Suffolk ewe. This neuroendocrine suppressionis mediated in part by dopamine A15 neurones, but these neurones do not possess the oestrogen receptor. Based on indirect evidence, we hypothesized that oestrogen receptor-containing neurones in the ventromedial preoptic area (vmPOA) may be the initial step in a neuronal system whereby oestradiol suppresses GnRH secretion during the non-breeding season. To test this, three experiments were conducted using ovariectomized ewes receiving either empty or oestradiol-containing bilateral microimplants directed at the vmPOA or s.c. subcutaneous oestradiol-containing implants. In the first experiment, LH pulse frequency was measured on days 0, 1, 7 and 14 of treatment during seasonal anoestrus. In vmPOA oestradiol and s.c. oestradiol groups only, LH pulse frequency was suppressed on days 7 and 14, with maximal suppression evident by day 7. In the second experiment, this protocol was repeated during the breeding season, with LH pulses examined on days 0 and 7; LH pulsefrequency did not change in any group. The third experiment tested if the effect of vmPOA oestradiol during anoestrus could be overcome by an injection of the dopamine-D-2 receptor antagonist (-)-sulpiride. The vmPOA microimplants and s.c. oestradiol implants again suppressed LH pulse frequency andthis was reversed by sulpiride in vmPOA oestradiol ewes. We conclude that oestradiol acts on cells in the vmPOA to stimulate a system involving dopamine neurones that inhibits GnRH/LH pulsatility in the anoestrous ewe.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/01/20 alle ore 14:31:22