Effects of a brief high-fat diet and acute exercise on the mTORC1 and IKK/NF-κB pathways in rat skeletal muscle.
Appl Physiol Nutr Metab
; 40(3): 251-62, 2015 Mar.
Article
en En
| MEDLINE
| ID: mdl-25706655
ABSTRACT
One exercise session can improve subsequent insulin-stimulated glucose uptake by skeletal muscle in healthy and insulin-resistant individuals. Our first aim was to determine whether a brief (2 weeks) high-fat diet (HFD) that caused muscle insulin resistance would activate the mammalian target of rapamycin complex 1 (mTORC1) and/or inhibitor of κB kinase/nuclear factor κB (IKK/NF-κB) pathways, which are potentially linked to induction of insulin resistance. Our second aim was to determine whether acute exercise that improved insulin-stimulated glucose uptake by muscles would attenuate activation of these pathways. We compared HFD-fed rats with rats fed a low-fat diet (LFD). Some animals from each diet group were sedentary and others were studied 3 h postexercise, when insulin-stimulated glucose uptake was increased. The results did not provide evidence that brief HFD activated either the mTORC1 (including phosphorylation of mTOR(Ser2448), TSC2(Ser939), p70S6K(Thr412), and RPS6(Ser235/236)) or the IKK/NF-κB (including abundance of IκBα or phosphorylation of NF-κB(Ser536), IKKα/ß(Ser177/181), and IκB(Ser32)) pathway in insulin-resistant muscles. Exercise did not oppose the activation of either pathway, as evidenced by no attenuation of phosphorylation of key proteins in the IKK/NF-κB pathway (NF-κB(Ser536), IKKα/ß(Ser177/181), and IκB(Ser32)), unaltered IκBα abundance, and no attenuation of phosphorylation of key proteins in the mTORC1 pathway (mTOR(Ser2448), TSC2(Ser939), and RPS6(Ser235/236)). Instead, exercise induced greater phosphorylation of 2 proteins of the mTORC1 pathway (PRAS40(Thr246) and p70S6K(Thr412)) in insulin-stimulated muscles, regardless of diet. Insulin resistance induced by a brief HFD was not attributable to greater activation of the mTORC1 or the IKK/NF-κB pathway in muscle, and exercise-induced improvement in insulin sensitivity was not attributable to attenuated activation of these pathways in muscle.
Palabras clave
Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Condicionamiento Físico Animal
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Grasas de la Dieta
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FN-kappa B
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Músculo Esquelético
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Complejos Multiproteicos
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Serina-Treonina Quinasas TOR
Límite:
Animals
Idioma:
En
Revista:
Appl Physiol Nutr Metab
Asunto de la revista:
CIENCIAS DA NUTRICAO
/
FISIOLOGIA
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MEDICINA ESPORTIVA
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METABOLISMO
Año:
2015
Tipo del documento:
Article
País de afiliación:
Estados Unidos