| |
|
|
|
Registro Completo |
|
Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
|
Data corrente: |
22/11/2002 |
|
Data da última atualização: |
22/11/2002 |
|
Autoria: |
TURZILLO, A. M.; CLAPPER, J. A.; MOSS, G. E.; NETT, T. M. |
|
Título: |
Regulation of ovine GnRH receptor gene expression by progesterone and oestradiol. |
|
Ano de publicação: |
1998 |
|
Fonte/Imprenta: |
Journal of Reproduction and Fertility, v. 113, n. 2, p. 251-256, 1998. |
|
Idioma: |
Inglês |
|
Conteúdo: |
The objective of this study was to determine whether progesterone prevents the stimulatory effects of oestradiol on GnRH receptor gene expression. In Expt 1, ewes were treated during the luteal phase (days 10-12 of the oestrous cycle) with either one or five subcutaneous implants containing oestradiol (n = 6 per group). Control ewes received no I treatment (n = 6). Anterior pituitary glands were collected 16 h after treatment with i oestradiol. Steady-state amounts of GnRH receptor mRNA were similar among all three I treatment groups despite increased circulating concentrations of oestradiol implanted ewes at the time of pituitary collection (4.3 +- 0.6 and 24.7 +- 2.6 pg ml-1 in ewes treated , with one or five implants, respectively, compared with 0.5 pg ml-1 in controls). Experiment 2 was designed to determine whether progesterone was the ovarian factor preventing the I stimulatory effects of oestradiol on. expression of the GnRH receptor gene in Expt 1. Twenty-five ewes were ovariectomized on day 6 or day 7 of the oestrous cycle and assigned to one of five treatment groups (n = 5 per group). Control ewes received no further treatment. Endogenous luteal phase concentrations of progesterone were replaced in three groups of ewes at the time of ovariectomy via intravaginal implants. Three days after ovariectomy, one group of progesterone-treated ewes received one oestradiol implant, while another group of progesterone-treated ewes received five oestradiol implants. An additional group was treated with five oestradiol implants only, and anterior pituitary glands were collected from alI ewes 16 h later. Compared with untreated ovariectomized ewes, treatment with progesterone alone did not affect amounts of GnRH receptor mRNA. In ewes treated with progesterone and either one or five oestradiol implants, steady-state amounts of GnRH receptor mRNA were increased twofold (P < 0.01). Treatment with oestradiol in the absence of progesterone increased amounts of GnRH receptor mRNA threefold (P < 0.001). These results provide evidence that the stimulatory effects of oestradiol on the expression of the GnRH receptor gene are prevented during the natural luteal phase in ewes. However, progesterone does not appear to act independently to mediate this effect. MenosThe objective of this study was to determine whether progesterone prevents the stimulatory effects of oestradiol on GnRH receptor gene expression. In Expt 1, ewes were treated during the luteal phase (days 10-12 of the oestrous cycle) with either one or five subcutaneous implants containing oestradiol (n = 6 per group). Control ewes received no I treatment (n = 6). Anterior pituitary glands were collected 16 h after treatment with i oestradiol. Steady-state amounts of GnRH receptor mRNA were similar among all three I treatment groups despite increased circulating concentrations of oestradiol implanted ewes at the time of pituitary collection (4.3 +- 0.6 and 24.7 +- 2.6 pg ml-1 in ewes treated , with one or five implants, respectively, compared with 0.5 pg ml-1 in controls). Experiment 2 was designed to determine whether progesterone was the ovarian factor preventing the I stimulatory effects of oestradiol on. expression of the GnRH receptor gene in Expt 1. Twenty-five ewes were ovariectomized on day 6 or day 7 of the oestrous cycle and assigned to one of five treatment groups (n = 5 per group). Control ewes received no further treatment. Endogenous luteal phase concentrations of progesterone were replaced in three groups of ewes at the time of ovariectomy via intravaginal implants. Three days after ovariectomy, one group of progesterone-treated ewes received one oestradiol implant, while another group of progesterone-treated ewes received five oestradiol implants. An additio... Mostrar Tudo |
|
Palavras-Chave: |
GnRH; Receptor. |
|
Thesagro: |
Endocrinologia; Estradiol; Hormônio; Ovino; Progesterona. |
|
Categoria do assunto: |
-- |
|
Marc: |
LEADER 02932naa a2200241 a 4500
001 1528866
005 2002-11-22
008 1998 bl uuuu u00u1 u #d
100 1 $aTURZILLO, A. M.
245 $aRegulation of ovine GnRH receptor gene expression by progesterone and oestradiol.
260 $c1998
520 $aThe objective of this study was to determine whether progesterone prevents the stimulatory effects of oestradiol on GnRH receptor gene expression. In Expt 1, ewes were treated during the luteal phase (days 10-12 of the oestrous cycle) with either one or five subcutaneous implants containing oestradiol (n = 6 per group). Control ewes received no I treatment (n = 6). Anterior pituitary glands were collected 16 h after treatment with i oestradiol. Steady-state amounts of GnRH receptor mRNA were similar among all three I treatment groups despite increased circulating concentrations of oestradiol implanted ewes at the time of pituitary collection (4.3 +- 0.6 and 24.7 +- 2.6 pg ml-1 in ewes treated , with one or five implants, respectively, compared with 0.5 pg ml-1 in controls). Experiment 2 was designed to determine whether progesterone was the ovarian factor preventing the I stimulatory effects of oestradiol on. expression of the GnRH receptor gene in Expt 1. Twenty-five ewes were ovariectomized on day 6 or day 7 of the oestrous cycle and assigned to one of five treatment groups (n = 5 per group). Control ewes received no further treatment. Endogenous luteal phase concentrations of progesterone were replaced in three groups of ewes at the time of ovariectomy via intravaginal implants. Three days after ovariectomy, one group of progesterone-treated ewes received one oestradiol implant, while another group of progesterone-treated ewes received five oestradiol implants. An additional group was treated with five oestradiol implants only, and anterior pituitary glands were collected from alI ewes 16 h later. Compared with untreated ovariectomized ewes, treatment with progesterone alone did not affect amounts of GnRH receptor mRNA. In ewes treated with progesterone and either one or five oestradiol implants, steady-state amounts of GnRH receptor mRNA were increased twofold (P < 0.01). Treatment with oestradiol in the absence of progesterone increased amounts of GnRH receptor mRNA threefold (P < 0.001). These results provide evidence that the stimulatory effects of oestradiol on the expression of the GnRH receptor gene are prevented during the natural luteal phase in ewes. However, progesterone does not appear to act independently to mediate this effect.
650 $aEndocrinologia
650 $aEstradiol
650 $aHormônio
650 $aOvino
650 $aProgesterona
653 $aGnRH
653 $aReceptor
700 1 $aCLAPPER, J. A.
700 1 $aMOSS, G. E.
700 1 $aNETT, T. M.
773 $tJournal of Reproduction and Fertility$gv. 113, n. 2, p. 251-256, 1998.
Download
Esconder MarcMostrar Marc Completo |
|
Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
|
|
Biblioteca |
ID |
Origem |
Tipo/Formato |
Classificação |
Cutter |
Registro |
Volume |
Status |
URL |
Voltar
|
|
|
 | Acesso ao texto completo restrito à biblioteca da Embrapa Unidades Centrais. Para informações adicionais entre em contato com biblioteca@embrapa.br. |
Registro Completo
|
Biblioteca(s): |
Embrapa Unidades Centrais. |
|
Data corrente: |
26/01/2005 |
|
Data da última atualização: |
27/11/2006 |
|
Autoria: |
BRESSAN, M.; MARTINS, M. C. |
|
Afiliação: |
Pesquisador Embrapa Gado de Leite. |
|
Título: |
Segurança alimentar na cadeia produtiva do leite e alguns de seus desafios. |
|
Ano de publicação: |
2004 |
|
Fonte/Imprenta: |
Revista de Política Agrícola, Brasília, ano 13, n.3, pag. 27-37, jul./set. 2004. |
|
Idioma: |
Português |
|
Conteúdo: |
O objetivo geral deste trabalho é ressaltar a importância da atividade leiteira em programas de segurança alimentar. Para tanto, é feita, em primeiro lugar, uma apresentação das principais restrições encontradas para o desenvolvimento da cadeia produtiva do leite no Brasil, a partir de um levantamento realizado nas Regiões Sul, Sudeste, Centro-Oeste, Nordeste e Norte, pelo Ministério da Ciência e Tecnologia (MCT) e pelo Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), em articulação com a Embrapa Gado de Leite e outras instituições. Como derivação desses problemas, faz-se, em segundo lugar, uma incursão conceitual sobre sustentabilidade e competitividade da atividade leiteira e suas relações com a questão da segurança alimentar. |
|
Palavras-Chave: |
Autonomia alimentar; Cadeia-Produtiva; Pecuária de leite; Produção-Leite; Projeto Plataforma; Segurança-Alimenta; Sustentabilidade. |
|
Thesagro: |
Cadeia Produtiva; Segurança Alimentar. |
|
Categoria do assunto: |
-- |
|
Marc: |
LEADER 01506naa a2200241 a 4500
001 1119634
005 2006-11-27
008 2004 bl uuuu u00u1 u #d
100 1 $aBRESSAN, M.
245 $aSegurança alimentar na cadeia produtiva do leite e alguns de seus desafios.
260 $c2004
520 $aO objetivo geral deste trabalho é ressaltar a importância da atividade leiteira em programas de segurança alimentar. Para tanto, é feita, em primeiro lugar, uma apresentação das principais restrições encontradas para o desenvolvimento da cadeia produtiva do leite no Brasil, a partir de um levantamento realizado nas Regiões Sul, Sudeste, Centro-Oeste, Nordeste e Norte, pelo Ministério da Ciência e Tecnologia (MCT) e pelo Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), em articulação com a Embrapa Gado de Leite e outras instituições. Como derivação desses problemas, faz-se, em segundo lugar, uma incursão conceitual sobre sustentabilidade e competitividade da atividade leiteira e suas relações com a questão da segurança alimentar.
650 $aCadeia Produtiva
650 $aSegurança Alimentar
653 $aAutonomia alimentar
653 $aCadeia-Produtiva
653 $aPecuária de leite
653 $aProdução-Leite
653 $aProjeto Plataforma
653 $aSegurança-Alimenta
653 $aSustentabilidade
700 1 $aMARTINS, M. C.
773 $tRevista de Política Agrícola, Brasília, ano 13$gn.3, pag. 27-37, jul./set. 2004.
Download
Esconder MarcMostrar Marc Completo |
|
Registro original: |
Embrapa Unidades Centrais (AI-SEDE) |
|
|
Nenhum exemplar cadastrado para este documento. |
Fechar
|
| Nenhum registro encontrado para a expressão de busca informada. |
|
|
