Document Detail

Activation of p38 mitogen-activated protein kinase alpha and beta by insulin and contraction in rat skeletal muscle: potential role in the stimulation of glucose transport.
MedLine Citation:
PMID:  11078445     Owner:  NLM     Status:  MEDLINE    
The stress-activated p38 mitogen-activated protein kinase (MAPK) was recently shown to be activated by insulin in muscle and adipose cells in culture. Here, we explore whether such stimulation is observed in rat skeletal muscle and whether muscle contraction can also affect the enzyme. Insulin injection (2 U over 3.5 min) resulted in increases in p38 MAPK phosphorylation measured in soleus (3.2-fold) and quadriceps (2.2-fold) muscles. Increased phosphorylation (3.5-fold) of an endogenous substrate of p38 MAPK, cAMP response element binder (CREB), was also observed. After in vivo insulin treatment, p38 MAPKalpha and p38 MAPKbeta isoforms were found to be activated (2.1- and 2.4-fold, respectively), using an in vitro kinase assay, in immunoprecipitates from quadriceps muscle extracts. In vitro insulin treatment (1 nmol/l over 4 min) and electrically-induced contraction of isolated extensor digitorum longus (EDL) muscle also doubled the kinase activity of p38 MAPKalpha and p38 MAPKbeta. The activity of both isoforms was inhibited in vitro by 10 micromol/l SB203580 in all muscles. To explore the possible participation of p38 MAPK in the stimulation of glucose uptake, EDL and soleus muscles were exposed to increasing doses of SB203580 before and during stimulation by insulin or contraction. SB203580 caused a significant reduction in the insulin- or contraction-stimulated 2-deoxyglucose uptake. Maximal inhibition (50-60%) occurred with 10 micromol/l SB203580. These results show that p38 MAPKalpha and -beta isoforms are activated by insulin and contraction in skeletal muscle. The data further suggest that activation of p38 MAPK may participate in the stimulation of glucose uptake by both stimuli in rat skeletal muscle.
R Somwar; M Perreault; S Kapur; C Taha; G Sweeney; T Ramlal; D Y Kim; J Keen; C H Côte; A Klip; A Marette
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Diabetes     Volume:  49     ISSN:  0012-1797     ISO Abbreviation:  Diabetes     Publication Date:  2000 Nov 
Date Detail:
Created Date:  2000-11-15     Completed Date:  2000-11-30     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0372763     Medline TA:  Diabetes     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1794-800     Citation Subset:  AIM; IM    
Programme in Cell Biology, Hospital for Sick Children, University of Toronto, Ontario, Canada.
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MeSH Terms
Cyclic AMP Response Element-Binding Protein / metabolism
Deoxyglucose / metabolism
Electric Stimulation
Enzyme Activation / drug effects
Enzyme Inhibitors / pharmacology
Imidazoles / pharmacology
Immunosorbent Techniques
Insulin / pharmacology*
Isoenzymes / metabolism*
Mitogen-Activated Protein Kinases / antagonists & inhibitors,  metabolism*
Muscle Contraction*
Muscle, Skeletal / enzymology*,  physiology
Pyridines / pharmacology
Rats, Wistar
p38 Mitogen-Activated Protein Kinases
Reg. No./Substance:
0/Cyclic AMP Response Element-Binding Protein; 0/Enzyme Inhibitors; 0/Imidazoles; 0/Isoenzymes; 0/Pyridines; 0/SB 203580; 11061-68-0/Insulin; 154-17-6/Deoxyglucose; EC Protein Kinases; EC Mitogen-Activated Protein Kinases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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