| A Single Prior Bout of Exercise Protects Against Palmitate-Induced Insulin Resistance Despite an Increase in Total Ceramide Content. | |
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MedLine Citation:
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PMID: 21325642 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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Ceramide accumulation has been implicated in the impairment of insulin-stimulated glucose transport in skeletal muscle following saturated fatty acid (FA) exposure. Importantly, a single bout of exercise can protect against acute lipid-induced insulin resistance. The mechanism by which exercise protects against lipid-induced insulin resistance is not completely known, but may occur through a redirection of FA toward triacylglycerol (TAG) and away from ceramide and diacylglycerol (DAG). Therefore, in the current study, an in vitro preparation was used to examine whether a prior bout of exercise could confer protection against palmitate-induced insulin resistance and whether the pharmacological (50 μM fumonisin B1 (FB1)) inhibition of ceramide synthesis in the presence of palmitate could mimic the protective effect of exercise. Soleus muscle of sedentary (SED), exercised (EX), and SED in the presence of FB1 (SED+FB1) were incubated with or without 2 mM palmitate for 4 hrs. 2 mM palmitate exposure impaired insulin-stimulated glucose transport (-28%, p<0.01) and significantly increased ceramide, DAG and TAG accumulation in the SED group (p<0.05). A single prior bout of exercise prevented the detrimental effects of palmitate on insulin signaling and caused a partial redistribution of FA toward TAG (+47%, p<0.05). However, the absolute increase in ceramide content in response to palmitate exposure in the EX group was not different compared to SED (+33% EX, p<0.05, vs. SED+FB1), despite the maintenance of insulin sensitivity. The incubation of soleus from SED rats with FB1 (SED+FB1) prevented the detrimental effects of palmitate and caused a redirection of FA toward TAG accumulation (p<0.05). Therefore, this research suggests that although inhibiting ceramide accumulation can prevent the detrimental effects of palmitate, a single prior bout of exercise appears to protect against palmitate-induced insulin resistance, which may be independent of changes in ceramide content. |
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Authors:
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A Brianne Thrush; Ewa Harasim; Adrian Chabowski; Roberto A Gulli; Leslie E Stefanyk; David J Dyck |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-2-16 |
Journal Detail:
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Title: American journal of physiology. Regulatory, integrative and comparative physiology Volume: - ISSN: 1522-1490 ISO Abbreviation: - Publication Date: 2011 Feb |
Date Detail:
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Created Date: 2011-2-17 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100901230 Medline TA: Am J Physiol Regul Integr Comp Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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1Univeristy of Guelph. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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