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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: |
ADAMS, T. E.; SAKURAI, H.; ADAMS, B. M. |
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Título: |
Effect of stress-like concentrations of cortisol on estradiol-dependent expression of gonadotropin-releasing hormone receptor 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. 164-168, 1999. |
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Idioma: |
Inglês |
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Conteúdo: |
The effect of stress-like concentrations of cortisol (C) on estrogen-dependent expression of GnRH receptor was evaluated using orchidectomized sheep (wethers; n = 6 anímais per group). C (5.0 mg/50 kg per hour; groups 1-4) or a comparable volume of vehicle (groups 5-8) was delivered by continuous in- fusion for 48 h. During the final 24 h of infusion, anímais received concurrent infusion of estradiol (E2) at rates of O (groups 1 and 5), 0.5 (groups 2 and 6), 2.0 (groups 3 and 7), or 8.0 (groups 4 and 8) Jl.g/50 kg per hour. Pituitary tissue was collected at the end of infusion. Although C did not affect (p > 0.05) the basal concentration of GnRH receptor or GnRH receptor mRNA, it reduced (p < 0.05) the increase in receptor and receptor mRNA induced by concurrent administration of 0.5 ug E2/50 kg per hour. In contrast, the increase in GnRH receptor expression induced by higher levels of estrogen stimulation was not affected (p > 0.05) by concurrent administration of C. The effect of C on the temporal pattern of E2-depen- dent increase in GnRH receptor expression was assessed using wethers receiving E2 (0.5 Jl.g/50 kg per hour) by continuous in- fusion for O (groups 1 and 5), 24 (groups 2 and 6), 48 (groups 3 and 7), or 72 h (groups 4 and 8). Animals received C (5.0 mg/ 50 kg per hour; groups 1-4) or vehicle (groups 5-8) beginning 24 h before, and continuing throughout, the E2 delivery period. Stress-like concentrations of C reduced (p < 0.05) the increase in GnRH receptor and receptor mRNA induced after 24 h of E2 stimulation. However, the suppressive effect of C was transient, and tissue levels of GnRH receptor and receptor mRNA were comparable after 72 h of E2 infusion in anímais receiving C or vehicle alone. Collectively these observations demonstrate that C suppresses estrogen-dependent increase in tissue concentrations of GnRH receptor and receptor mRNA. However, this effect of C is transient and not evident in animals receiving moderate to high levels of estrogen stimulation. This transient suppression of GnRH receptor expression mar account, at least in part, for the anti-gonadal effect of glucocorticoids. MenosThe effect of stress-like concentrations of cortisol (C) on estrogen-dependent expression of GnRH receptor was evaluated using orchidectomized sheep (wethers; n = 6 anímais per group). C (5.0 mg/50 kg per hour; groups 1-4) or a comparable volume of vehicle (groups 5-8) was delivered by continuous in- fusion for 48 h. During the final 24 h of infusion, anímais received concurrent infusion of estradiol (E2) at rates of O (groups 1 and 5), 0.5 (groups 2 and 6), 2.0 (groups 3 and 7), or 8.0 (groups 4 and 8) Jl.g/50 kg per hour. Pituitary tissue was collected at the end of infusion. Although C did not affect (p > 0.05) the basal concentration of GnRH receptor or GnRH receptor mRNA, it reduced (p < 0.05) the increase in receptor and receptor mRNA induced by concurrent administration of 0.5 ug E2/50 kg per hour. In contrast, the increase in GnRH receptor expression induced by higher levels of estrogen stimulation was not affected (p > 0.05) by concurrent administration of C. The effect of C on the temporal pattern of E2-depen- dent increase in GnRH receptor expression was assessed using wethers receiving E2 (0.5 Jl.g/50 kg per hour) by continuous in- fusion for O (groups 1 and 5), 24 (groups 2 and 6), 48 (groups 3 and 7), or 72 h (groups 4 and 8). Animals received C (5.0 mg/ 50 kg per hour; groups 1-4) or vehicle (groups 5-8) beginning 24 h before, and continuing throughout, the E2 delivery period. Stress-like concentrations of C reduced (p < 0.05) the increase in GnRH receptor and... Mostrar Tudo |
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Palavras-Chave: |
Gonadotropina; Receptor. |
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Thesagro: |
Estradiol; Hormônio; Ovino; Stress. |
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Thesaurus Nal: |
cortisol. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02823naa a2200229 a 4500
001 1528814
005 2002-11-06
008 1999 bl uuuu u00u1 u #d
100 1 $aADAMS, T. E.
245 $aEffect of stress-like concentrations of cortisol on estradiol-dependent expression of gonadotropin-releasing hormone receptor in orchidectomized sheep.
260 $c1999
520 $aThe effect of stress-like concentrations of cortisol (C) on estrogen-dependent expression of GnRH receptor was evaluated using orchidectomized sheep (wethers; n = 6 anímais per group). C (5.0 mg/50 kg per hour; groups 1-4) or a comparable volume of vehicle (groups 5-8) was delivered by continuous in- fusion for 48 h. During the final 24 h of infusion, anímais received concurrent infusion of estradiol (E2) at rates of O (groups 1 and 5), 0.5 (groups 2 and 6), 2.0 (groups 3 and 7), or 8.0 (groups 4 and 8) Jl.g/50 kg per hour. Pituitary tissue was collected at the end of infusion. Although C did not affect (p > 0.05) the basal concentration of GnRH receptor or GnRH receptor mRNA, it reduced (p < 0.05) the increase in receptor and receptor mRNA induced by concurrent administration of 0.5 ug E2/50 kg per hour. In contrast, the increase in GnRH receptor expression induced by higher levels of estrogen stimulation was not affected (p > 0.05) by concurrent administration of C. The effect of C on the temporal pattern of E2-depen- dent increase in GnRH receptor expression was assessed using wethers receiving E2 (0.5 Jl.g/50 kg per hour) by continuous in- fusion for O (groups 1 and 5), 24 (groups 2 and 6), 48 (groups 3 and 7), or 72 h (groups 4 and 8). Animals received C (5.0 mg/ 50 kg per hour; groups 1-4) or vehicle (groups 5-8) beginning 24 h before, and continuing throughout, the E2 delivery period. Stress-like concentrations of C reduced (p < 0.05) the increase in GnRH receptor and receptor mRNA induced after 24 h of E2 stimulation. However, the suppressive effect of C was transient, and tissue levels of GnRH receptor and receptor mRNA were comparable after 72 h of E2 infusion in anímais receiving C or vehicle alone. Collectively these observations demonstrate that C suppresses estrogen-dependent increase in tissue concentrations of GnRH receptor and receptor mRNA. However, this effect of C is transient and not evident in animals receiving moderate to high levels of estrogen stimulation. This transient suppression of GnRH receptor expression mar account, at least in part, for the anti-gonadal effect of glucocorticoids.
650 $acortisol
650 $aEstradiol
650 $aHormônio
650 $aOvino
650 $aStress
653 $aGonadotropina
653 $aReceptor
700 1 $aSAKURAI, H.
700 1 $aADAMS, B. M.
773 $tBiology of Reproduction$gv. 60, n. 1, p. 164-168, 1999.
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Embrapa Caprinos e Ovinos (CNPC) |
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