| Additive effect of contraction and insulin on glucose uptake and glycogen synthase in muscle with different glycogen contents. | |
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MedLine Citation:
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PMID: 20185632 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Insulin and contraction regulate glucose uptake and glycogen synthase (GS) via distinct mechanisms in skeletal muscles, and an additive effect has been reported. Glycogen content is known to influence both contraction- and insulin-stimulated glucose uptake and GS activity. Our study reports that contraction and insulin additively stimulate glucose uptake in rat epitrochlearis muscles with normal (NG) and high (HG) glycogen contents, but the additive effect was only partial. In muscles with low glycogen (LG) content no additive effect was seen, but glucose uptake was higher in LG than in NG and HG during contraction, insulin stimulation, and when the two stimuli were combined. In LG, contraction-stimulated AMP-activated protein kinase (AMPK) activity and insulin-stimulated PKB phosphorylation were higher than in NG and HG, but phosphorylation of Akt substrate of 160 kDa was not elevated correspondingly. GLUT4 content was 50% increased in LG (rats fasted 24 h), which may explain the increased glucose uptake. Contraction and insulin also additively increased GS fractional activity in NG and HG but not in LG. GS fractional activity correlated most strongly with GS Ser641 phosphorylation (R -0.94, P<0.001). GS fractional activity also correlated with GS Ser7,10 phosphorylation, but insulin did not reduce GS Ser7,10 phosphorylation. In conclusion, an additive effect of contraction and insulin on glucose uptake and GS activity occurs in muscles with normal and high glycogen content but not in muscles with low glycogen content. Furthermore, contraction, insulin, and glycogen content all regulate GS Ser641 phosphorylation and GS fractional activity in concert. |
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Authors:
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Yu-Chiang Lai; Elham Zarrinpashneh; Jørgen Jensen |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-02-25 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 108 ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2010 May |
Date Detail:
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Created Date: 2010-05-05 Completed Date: 2010-08-12 Revised Date: 2011-11-04 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1106-15 Citation Subset: IM |
Affiliation:
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Department of Physiology, National Institute of Occupational Health, Oslo, Norway. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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AMP-Activated Protein Kinases
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metabolism Animals Food Deprivation GTPase-Activating Proteins / metabolism Glucose / metabolism* Glucose Transporter Type 4 / metabolism Glycogen / metabolism* Glycogen Synthase / metabolism* Hexokinase / metabolism Insulin / metabolism* Male Muscle Contraction* Muscle, Skeletal / enzymology* Phosphorylation Proto-Oncogene Proteins c-akt / metabolism Rats Rats, Wistar Serine Signal Transduction Time Factors |
| Chemical | |
Reg. No./Substance:
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0/GTPase-Activating Proteins; 0/Glucose Transporter Type 4; 0/LOC686547 protein, rat; 0/Slc2a4 protein, rat; 11061-68-0/Insulin; 50-99-7/Glucose; 56-45-1/Serine; 9005-79-2/Glycogen; EC 2.4.1.11/Glycogen Synthase; EC 2.7.1.1/Hexokinase; EC 2.7.11.1/AMP-Activated Protein Kinases; EC 2.7.11.1/Proto-Oncogene Proteins c-akt |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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