Document Detail

AMPK activation is fiber type specific in human skeletal muscle: effects of exercise and short-term exercise training.
MedLine Citation:
PMID:  19359609     Owner:  NLM     Status:  MEDLINE    
AMP-activated protein kinase (AMPK) has been extensively studied in whole muscle biopsy samples of humans, yet the fiber type-specific expression and/or activation of AMPK is unknown. We examined basal and exercise AMPK-alpha Thr(172) phosphorylation and AMPK subunit expression (alpha(1), alpha(2), and gamma(3)) in type I, IIa, and IIx fibers of human skeletal muscle before and after 10 days of exercise training. Before training basal AMPK phosphorylation was greatest in type IIa fibers (P < 0.05 vs. type I and IIx), while an acute bout of exercise increased AMPK phosphorylation in all fibers (P < 0.05), with the greatest increase occurring in type IIx fibers. Exercise training significantly increased basal AMPK phosphorylation in all fibers, and the exercise-induced increases were uniformly suppressed compared with pretraining exercise. Expression of AMPK-alpha(1) and -alpha(2) was similar between fibers and was not altered by exercise training. However, AMPK-gamma(3) was differentially expressed in skeletal muscle fibers (type IIx > type IIa > type I), irrespective of training status. Thus skeletal muscle AMPK phosphorylation and AMPK expression are fiber type specific in humans in the basal state, as well as during exercise. Our findings reveal fiber type-specific differences that have been masked in previous studies examining mixed muscle samples.
Robert S Lee-Young; Benedict J Canny; Damian E Myers; Glenn K McConell
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-04-09
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  107     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2009 Jul 
Date Detail:
Created Date:  2009-07-01     Completed Date:  2009-08-28     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  283-9     Citation Subset:  IM    
Department of Physiology, University of Melbourne, Parkville, Victoria.
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MeSH Terms
AMP-Activated Protein Kinases / biosynthesis,  metabolism*
Biological Markers / metabolism
Exercise / physiology*
Muscle Fibers, Skeletal / chemistry,  classification,  enzymology*
Oxygen Consumption
Physical Fitness / physiology*
Young Adult
Reg. No./Substance:
0/Biological Markers; EC Protein Kinases; EC protein, human

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

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