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 | Acesso ao texto completo restrito à biblioteca da Embrapa Caprinos e Ovinos. Para informações adicionais entre em contato com cnpc.biblioteca@embrapa.br. |
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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
01/08/1992 |
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Data da última atualização: |
23/05/2023 |
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Autoria: |
FOSTER, D. L.; ROACH, J. F.; KARSCH, F. J.; NORTON, H. W.; COOK, B.; NALBANDOV, A. V. |
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Título: |
Regulation of luteinizing hormone in the fetal and neonatal lamb. I. LH concentrations in blood and pituitary. |
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Ano de publicação: |
1972 |
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Fonte/Imprenta: |
Endocrinology, v. 90, n. 1, p. 102-111, Jan. 1972. |
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DOI: |
10.1210/endo-90-1-102 |
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Idioma: |
Inglês |
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Conteúdo: |
Abstract: LH was studied in 504 lambs during the last two-thirds of prenatal development through day 18 of postnatal life using specific and sensitive radioimmunoassays to quantitate LH in small amounts of sera and anterior pituitaries. The increase in both pituitary LH concentration and gonadal weight with fetal age was greater for males than females. Despite the elevated concentrations of LH in the fetal pituitary during the final third of gestation, circulating LH in both sexes decreased to the lowest levels observed during fetal life. However, these changes in pituitary and serum LH concentrations during prenatal development were different for the two sexes but seemed unrelated to the differential growth of the gonads. Although the concentration of LH in fetal serum was not influenced by the presence of a twin, twins of either sex had a lower concentration of pituitary LH than singletons. The sex of the co-twin had no effect on this parameter. A precipitous decrease in pituitary LH occurred in lambs of both sexes at parturition, but no evidence was obtained for concomitantly increased serum LH concentration during the immediate postnatal period. Fetal testicular steroid hormone and maternoplacental effects on the prenatal pituitary are suggested to account for differences between the sexes and the effect of twinning on the synthesis and release of LH during the prenatal and early postnatal period. Sex differences in LH regulation continued in neonatal life. The plateau in concentrations of pituitary and serum LH in males and the increase in concentration of both pituitary and serum LH in females after birth suggest that negative feedback of gonadal steroids on the hypothalamohypophyseal axis of the neonate becomes established earlier in males than in females. MenosAbstract: LH was studied in 504 lambs during the last two-thirds of prenatal development through day 18 of postnatal life using specific and sensitive radioimmunoassays to quantitate LH in small amounts of sera and anterior pituitaries. The increase in both pituitary LH concentration and gonadal weight with fetal age was greater for males than females. Despite the elevated concentrations of LH in the fetal pituitary during the final third of gestation, circulating LH in both sexes decreased to the lowest levels observed during fetal life. However, these changes in pituitary and serum LH concentrations during prenatal development were different for the two sexes but seemed unrelated to the differential growth of the gonads. Although the concentration of LH in fetal serum was not influenced by the presence of a twin, twins of either sex had a lower concentration of pituitary LH than singletons. The sex of the co-twin had no effect on this parameter. A precipitous decrease in pituitary LH occurred in lambs of both sexes at parturition, but no evidence was obtained for concomitantly increased serum LH concentration during the immediate postnatal period. Fetal testicular steroid hormone and maternoplacental effects on the prenatal pituitary are suggested to account for differences between the sexes and the effect of twinning on the synthesis and release of LH during the prenatal and early postnatal period. Sex differences in LH regulation continued in neonatal life. The plateau i... Mostrar Tudo |
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Palavras-Chave: |
Hormônio luteinizante; Sex Factors. |
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Thesagro: |
Endocrinologia; Fisiologia; Ovino; Reprodução. |
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Thesaurus Nal: |
Hypothalamus; Pituitary gland; Postpartum period; Pregnancy; Radioimmunoassays; Reproduction; Sheep; Twins. |
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Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
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Marc: |
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Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
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| 1. |  | CHICHORRO, J. F.; SILVA, A. L. P. da; ANDRADE, W. S. de P.; HEGEDUS, C. E. N.; KUBOYAMA, F. A. Q. Custos e índices econômicos de povoamentos de eucalipto do Programa Produtor Florestal no Espírito Santo. Pesquisa Florestal Brasileira, Colombo, v. 37, n. 92, p. 447-456, out./dez. 2017.| Biblioteca(s): Embrapa Florestas. |
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| Registros recuperados : 1 | |
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