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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
06/11/2002 |
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Data da última atualização: |
06/11/2002 |
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Autoria: |
DALEY, C. A.; SAKURAI, H.; ADAMS, B. M.; ADAMS, T. E. |
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Título: |
Effect of stress-like concentrations of cortisol on gonadotroph function in orchidectomized sheep. |
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Ano de publicação: |
1999 |
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Fonte/Imprenta: |
Biology of Reproduction, v. 60, n. 1, p. 158-163, 1999. |
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Idioma: |
Inglês |
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Conteúdo: |
The effect of stress-like concentrations of cortisol (C) on the feedback potency of estradiol (E,) was assessed using 32 orchidectomized sheep (wethers) assigned at random to 1 of 4 treatment groups in a 2 x 2 factorial design. Wethers received C (3.6 mg/50 kg per hour; groups 2 and 4) or a comparable volume of C delivery vehicle (groups 1 and 3) as a continuous infusion for 7 days. During the final 48 h of infusion, wethers received E2 (0.3 ug/50 kg/h; groups 3 and 4) or E2 delivery vehicle (groups 1 and 2). The pattern of LH secretion was assessed during a 4 h period of intensive blood collection beginning 44 h after initiation of E2 infusion. Gonadotroph responsiveness (LH secretion induced by GnRH challenge [500 ng, i.v.]) was determined 48 h after E2 delivery was begun. Although lhe frequency of secretory episodes of LH was not affected (p > 0.05) by infusion of C or E2 alone, LH pulse frequency was significantly decreased in wethers receiving C and E2 in combination. In contrast, neither the magnitude of basal gonadotroph responsiveness nor the extent of E2-dependent augmentation of responsiveness was significantly affected by stress-like concentrations of C. In a second experiment, the effect of C on the magnitude of E2-induced in- crease in pituitary concentration of GnRH receptor and GnRH receptor mRNA was assessed using 32 additional wethers. Continuous infusion of E2 for 48 h increased (p < 0.05) tissue concentrations of GnRH receptor and GnRH receptor mRNA. Con- current delivery of C did not affect (p > 0.05) E2-induced in- crease in GnRH receptor mRNA but significantly reduced the magnitude of the E2-dependent increase in pituitary concentration of GnRH receptor. Collectively, these data indicate that stress-like concentrations of C enhance the negative feedback potency of E2 and reduce estrogen-dependent augmentation of the concentration of GnRH receptor in pituitary tissue. MenosThe effect of stress-like concentrations of cortisol (C) on the feedback potency of estradiol (E,) was assessed using 32 orchidectomized sheep (wethers) assigned at random to 1 of 4 treatment groups in a 2 x 2 factorial design. Wethers received C (3.6 mg/50 kg per hour; groups 2 and 4) or a comparable volume of C delivery vehicle (groups 1 and 3) as a continuous infusion for 7 days. During the final 48 h of infusion, wethers received E2 (0.3 ug/50 kg/h; groups 3 and 4) or E2 delivery vehicle (groups 1 and 2). The pattern of LH secretion was assessed during a 4 h period of intensive blood collection beginning 44 h after initiation of E2 infusion. Gonadotroph responsiveness (LH secretion induced by GnRH challenge [500 ng, i.v.]) was determined 48 h after E2 delivery was begun. Although lhe frequency of secretory episodes of LH was not affected (p > 0.05) by infusion of C or E2 alone, LH pulse frequency was significantly decreased in wethers receiving C and E2 in combination. In contrast, neither the magnitude of basal gonadotroph responsiveness nor the extent of E2-dependent augmentation of responsiveness was significantly affected by stress-like concentrations of C. In a second experiment, the effect of C on the magnitude of E2-induced in- crease in pituitary concentration of GnRH receptor and GnRH receptor mRNA was assessed using 32 additional wethers. Continuous infusion of E2 for 48 h increased (p < 0.05) tissue concentrations of GnRH receptor and GnRH receptor mRNA. Con- ... Mostrar Tudo |
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Palavras-Chave: |
Gonadotropina. |
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Thesagro: |
Hormônio; Ovino; Stress. |
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Thesaurus Nal: |
cortisol. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02515naa a2200217 a 4500
001 1528806
005 2002-11-06
008 1999 bl uuuu u00u1 u #d
100 1 $aDALEY, C. A.
245 $aEffect of stress-like concentrations of cortisol on gonadotroph function in orchidectomized sheep.
260 $c1999
520 $aThe effect of stress-like concentrations of cortisol (C) on the feedback potency of estradiol (E,) was assessed using 32 orchidectomized sheep (wethers) assigned at random to 1 of 4 treatment groups in a 2 x 2 factorial design. Wethers received C (3.6 mg/50 kg per hour; groups 2 and 4) or a comparable volume of C delivery vehicle (groups 1 and 3) as a continuous infusion for 7 days. During the final 48 h of infusion, wethers received E2 (0.3 ug/50 kg/h; groups 3 and 4) or E2 delivery vehicle (groups 1 and 2). The pattern of LH secretion was assessed during a 4 h period of intensive blood collection beginning 44 h after initiation of E2 infusion. Gonadotroph responsiveness (LH secretion induced by GnRH challenge [500 ng, i.v.]) was determined 48 h after E2 delivery was begun. Although lhe frequency of secretory episodes of LH was not affected (p > 0.05) by infusion of C or E2 alone, LH pulse frequency was significantly decreased in wethers receiving C and E2 in combination. In contrast, neither the magnitude of basal gonadotroph responsiveness nor the extent of E2-dependent augmentation of responsiveness was significantly affected by stress-like concentrations of C. In a second experiment, the effect of C on the magnitude of E2-induced in- crease in pituitary concentration of GnRH receptor and GnRH receptor mRNA was assessed using 32 additional wethers. Continuous infusion of E2 for 48 h increased (p < 0.05) tissue concentrations of GnRH receptor and GnRH receptor mRNA. Con- current delivery of C did not affect (p > 0.05) E2-induced in- crease in GnRH receptor mRNA but significantly reduced the magnitude of the E2-dependent increase in pituitary concentration of GnRH receptor. Collectively, these data indicate that stress-like concentrations of C enhance the negative feedback potency of E2 and reduce estrogen-dependent augmentation of the concentration of GnRH receptor in pituitary tissue.
650 $acortisol
650 $aHormônio
650 $aOvino
650 $aStress
653 $aGonadotropina
700 1 $aSAKURAI, H.
700 1 $aADAMS, B. M.
700 1 $aADAMS, T. E.
773 $tBiology of Reproduction$gv. 60, n. 1, p. 158-163, 1999.
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Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
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 | Acesso ao texto completo restrito à biblioteca da Embrapa Soja. Para informações adicionais entre em contato com valeria.cardoso@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Soja. |
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Data corrente: |
01/03/2024 |
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Data da última atualização: |
01/03/2024 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Circulação/Nível: |
C - 0 |
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Autoria: |
PESKE, S. T.; FRANÇA-NETO, J. B. |
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Afiliação: |
SILMAR TEICHERT PESKE; JOSE DE BARROS FRANCA NETO, CNPSO. |
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Título: |
A pirataria de sementes. |
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Ano de publicação: |
2024 |
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Fonte/Imprenta: |
Seed News, v. 28, n. 2, p. 36-40, 2024. |
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Idioma: |
Português |
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Thesagro: |
Semente. |
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Thesaurus NAL: |
Seeds. |
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Categoria do assunto: |
X Pesquisa, Tecnologia e Engenharia |
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Marc: |
LEADER 00374naa a2200145 a 4500
001 2162461
005 2024-03-01
008 2024 bl uuuu u00u1 u #d
100 1 $aPESKE, S. T.
245 $aA pirataria de sementes.$h[electronic resource]
260 $c2024
650 $aSeeds
650 $aSemente
700 1 $aFRANÇA-NETO, J. B.
773 $tSeed News$gv. 28, n. 2, p. 36-40, 2024.
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Embrapa Soja (CNPSO) |
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