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Titolo:
COMPARATIVE-STUDY BETWEEN PONY MARES AND EWES EVALUATING GONADOTROPICRESPONSE TO ADMINISTRATION OF GONADOTROPIN-RELEASING-HORMONE
Autore:
PORTER MB; CLEAVER BD; PELTIER M; ROBINSON G; THATCHER WW; SHARP DC;
Indirizzi:
UNIV FLORIDA,DEPT ANIM SCI GAINESVILLE FL 32611 UNIV FLORIDA,DEPT ANIM SCI GAINESVILLE FL 32611 UNIV FLORIDA,DEPT DAIRY SCI GAINESVILLE FL 32611
Titolo Testata:
Journal of Reproduction and Fertility
fascicolo: 2, volume: 110, anno: 1997,
pagine: 219 - 229
SICI:
0022-4251(1997)110:2<219:CBPMAE>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
MESSENGER-RNA LEVELS; LUTEINIZING-HORMONE; DOWN-REGULATION; GNRH-RECEPTOR; PERIOVULATORY PERIOD; SECRETION RATES; PITUITARY; AGONIST; PULSE; LH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
36
Recensione:
Indirizzi per estratti:
Citazione:
M.B. Porter et al., "COMPARATIVE-STUDY BETWEEN PONY MARES AND EWES EVALUATING GONADOTROPICRESPONSE TO ADMINISTRATION OF GONADOTROPIN-RELEASING-HORMONE", Journal of Reproduction and Fertility, 110(2), 1997, pp. 219-229

Abstract

This study compared equine and ovine LH secretory responses to GnRH treatment. Dioestrous mares and ewes were challenged with continuous GnRH for 15 h. Mares that received constant GnRH (110 mu g h(-1)) had sustained LH secretion (P < 0.01), whereas LH concentrations in ewes treated with continuous GnRH (25 mu g h(-1)) initially increased, then declined and remained low, suggesting GnRH receptor desensitization or downregulation. In addition, progesterone-primed, ovariectomized mares and ewes were challenged with pulsatile or continuous GnRH for 5 days. Plasma LH concentrations were increased by day 5 in mares treated with pulsatile (25 mu g pulse(-1) h(-1)) and continuous (110 mu g h(-1)) GnRH (P<0.01). Furthermore, mean LH concentrations and time-response curves were not different. In contrast, ewes treated with continuous GnRH (2.5 mu g h(-1)) demonstrated LH secretory patterns indicative of GnRH receptor downregulation on day I of treatment. LH concentrations in ewes treated with pulsatile GnRH (250 ng pulse(-1) h(-1)) did not differ from controls. In conclusion, pony mares responded continuously to GnRH treatment (pulsatile and continuous), whereas ewes treated withcontinuous GnRH experienced reduced LH secretion. These findings suggest a unique hypothalamic-pituitary axis in pony mares.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 07:43:52