| Exercise improves skeletal muscle insulin resistance without reduced basal mTOR/S6K1 signaling in rats fed a high-fat diet. | |
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MedLine Citation:
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PMID: 21404070 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Exercise improves high-fat diet (HFD)-induced skeletal muscle insulin resistance, but the mechanism is unresolved. This study aims to explore whether the improvement in response to exercise is associated with mTOR/S6K1 signaling and whether the signaling changes are muscle-specific. Male SD rats (150-180 g) were used for this study. After the experimental period, 6 weeks of exercise improved HFD-impaired intraperitoneal glucose tolerance and insulin-stimulated 2-deoxyglucose uptake in soleus (SOL) and extensor digitorum longus (EDL) muscles. Furthermore, 6 weeks of the HFD resulted in a reduced type I fiber ratio of SOL, an increased type I ratio of EDL, and a reduced fiber size of EDL, whereas exercise increased type I fiber ratio of SOL as well as type I fiber cross-sectional areas of EDL. However, the HFD had a main effect on basal cytosolic phosphorylation of S6K1 on Thr(389) content in SOL, which was also influenced by a significant interaction between the diet and exercise in EDL. Exercise had no direct effect on the basal phosphorylation of Akt on Ser(473), mTOR on Ser(2448), S6K1 on Thr(389) content in SOL. On the contrary, exercise prevented HFD-induced decrease in basal phosphorylation of S6K1 on Thr(389) content in EDL. These results indicate that 6 weeks of HFD and exercise lead to alterations in fiber type shift, fiber size, and basal phosphorylation of S6K1 on Thr(389) content in a muscle-specific pattern. Exercise prevents HFD-induced skeletal muscle insulin resistance, which is not associated with a reduced basal phosphorylation of mTOR/S6K1 alteration in the muscles. |
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Authors:
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Bagen Liao; Yong Xu |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-3-15 |
Journal Detail:
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Title: European journal of applied physiology Volume: - ISSN: 1439-6327 ISO Abbreviation: - Publication Date: 2011 Mar |
Date Detail:
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Created Date: 2011-3-15 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100954790 Medline TA: Eur J Appl Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Department of Sports Medicine, Guangzhou Sports University, Guangzhou Dadao 1268, Guangzhou, 510076, China, bagen2005@yahoo.com.cn. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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