RESUMO
The purpose of this study was to investigate the effect of T3 on amino acid accumulation and on the membrane potential of Sertoli cells of immature rat testes. Testes of pre-pubertal and pubertal rats were pre-incubated (30 min) in Krebs-Ringer bicarbonate buffer and incubated in the presence of [14C]methylaminoisobutyric acid with and without T3 for 15, 45 and 60 min. The hormone (10(-6) M and 10(-7) M) significantly stimulated amino acid accumulation in 6 and 13-day old rat testes but did not have any effect in neonatal and pubertal animals. T3 produced a dose-dependent hyperpolarizing effect at concentrations of 10(-6) M, 10(-5) M, 2 x 10(-5) M and 10(-4) M. We conclude that T3 induces a membrane hyperpolarization in Sertoli cells and stimulates amino acid accumulation in immature rat testes, demonstrating that the hormone has a rapid plasma membrane action.
Assuntos
Aminoácidos/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Testículo/efeitos dos fármacos , Tri-Iodotironina/farmacologia , beta-Alanina/análogos & derivados , Animais , Cálcio/metabolismo , Masculino , Ratos , Ratos Wistar , Células de Sertoli/efeitos dos fármacos , Células de Sertoli/metabolismo , Maturidade Sexual , beta-Alanina/metabolismoRESUMO
In this review main hormones involved in development and muscle growth are shown with special emphasis on growth hormone (GH) and insulin-like growth factors (IGF). Chemist composition, synthesis place, action way and main action mechanisms of these hormones are reviewed. Nutritional factors which modified seric metabolites, and their effects on hormone secretion are detailed. It was observed that GH, IGF, thyroid hormones, insulin, glucocorticoids and sexual steroids act in a complex and cordinated way to produce a productive response to different> nutritional strategies.
Assuntos
Animais Domésticos/crescimento & desenvolvimento , Hormônio do Crescimento Humano/fisiologia , Somatomedinas/fisiologia , Animais , Glucocorticoides/fisiologia , Hormônio do Crescimento Humano/sangue , Insulina/fisiologia , Desenvolvimento Muscular , Estado Nutricional , Somatomedinas/análise , Hormônios Tireóideos/fisiologiaRESUMO
En esta revisión se describen las principales hormonas invlolucradas en el desarrollo y crecimiento muscular, haciendo especial énfasis en la hormona de cricimiento (GH) y los factores del crecimiento semejante a insulina (IGF). Se recopila la composición química, el lugar de síntesis y los principales mecanismos de acción de estas hormonas. Se observó que la GH, IGF, las hormonas tiroideas, la insulina, los glucocorticoides y los esteroides sexuales actuán en una forma compleja y coordinada para producir una respuesta productiva a diferentes estrategias nutricionales.
Assuntos
Animais , Animais Domésticos/crescimento & desenvolvimento , Hormônio do Crescimento Humano/fisiologia , Estado Nutricional , Somatomedinas/fisiologia , Glucocorticoides/fisiologia , Hormônio do Crescimento Humano/sangue , Insulina/fisiologia , Músculos/crescimento & desenvolvimento , Somatomedinas/análise , Hormônios Tireóideos/fisiologiaRESUMO
In this review main hormones involved in development and muscle growth are shown with special emphasis on growth hormone (GH) and insulin-like growth factors (IGF). Chemist composition, synthesis place, action way and main action mechanisms of these hormones are reviewed. Nutritional factors which modified seric metabolites, and their effects on hormone secretion are detailed. It was observed that GH, IGF, thyroid hormones, insulin, glucocorticoids and sexual steroids act in a complex and cordinated way to produce a productive response to different> nutritional strategies.
RESUMO
En esta revisión se describen las principales hormonas invlolucradas en el desarrollo y crecimiento muscular, haciendo especial énfasis en la hormona de cricimiento (GH) y los factores del crecimiento semejante a insulina (IGF). Se recopila la composición química, el lugar de síntesis y los principales mecanismos de acción de estas hormonas. Se observó que la GH, IGF, las hormonas tiroideas, la insulina, los glucocorticoides y los esteroides sexuales actuán en una forma compleja y coordinada para producir una respuesta productiva a diferentes estrategias nutricionales. (AU)
Assuntos
Animais , Estado Nutricional , Hormônio do Crescimento Humano/fisiologia , Somatomedinas/fisiologia , Animais Domésticos/crescimento & desenvolvimento , Hormônio do Crescimento Humano/sangue , Somatomedinas/análise , Músculos/crescimento & desenvolvimento , Hormônios Tireóideos/fisiologia , Insulina/fisiologia , Glucocorticoides/fisiologiaRESUMO
During outbreaks of dengue fever in the Caribbean in 1977 and 1978 a continuous cell line derived from Aedes pseudoscutellaris was successfully used for the isolation of dengue virus strains from acute human sera. 238 strains were isolated and culture fluid was successfully used as antigen for the identification of several strains. The isolates all produced a marked syncytial cytopathic effect often visible as early as four days after inoculation. The method was successfully employed in the field where, because of their low optimal incubation temperature, the cells suffered no ill effects under ambient conditions. The isolation method was found to be much more sensitive than conventional mouse inoculation.