Exercise training improves muscle insulin resistance but not insulin receptor signaling in obese Zucker rats.
J Appl Physiol (1985)
; 92(2): 736-44, 2002 Feb.
Article
em En
| MEDLINE
| ID: mdl-11796688
ABSTRACT
Exercise training improves skeletal muscle insulin sensitivity in the obese Zucker rat. The purpose of this study was to investigate whether the improvement in insulin action in response to exercise training is associated with enhanced insulin receptor signaling. Obese Zucker rats were trained for 7 wk and studied by using the hindlimb-perfusion technique 24 h, 96 h, or 7 days after their last exercise training bout. Insulin-stimulated glucose uptake (traced with 2-deoxyglucose) was significantly reduced in untrained obese Zucker rats compared with lean controls (2.2 +/- 0.17 vs. 5.4 +/- 0.46 micromol x g(-1) x h(-1)). Glucose uptake was normalized 24 h after the last exercise bout (4.9 +/- 0.41 micromol x g(-1) x h(-1)) and remained significantly elevated above the untrained obese Zucker rats for 7 days. However, exercise training did not increase insulin receptor or insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation, phosphatidylinositol 3-kinase (PI3-kinase) activity associated with IRS-1 or tyrosine phosphorylated immunoprecipitates, or Akt serine phosphorylation. These results are consistent with the hypothesis that, in obese Zucker rats, adaptations occur during training that lead to improved insulin-stimulated muscle glucose uptake without affecting insulin receptor signaling through the PI3-kinase pathway.
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Base de dados:
MEDLINE
Assunto principal:
Condicionamento Físico Animal
/
Ratos Zucker
/
Resistência à Insulina
/
Receptor de Insulina
/
Transdução de Sinais
/
Proteínas Serina-Treonina Quinases
/
Músculo Esquelético
/
Proteínas Musculares
/
Obesidade
Limite:
Animals
Idioma:
En
Revista:
J Appl Physiol (1985)
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos