Document Detail


Obesity impairs skeletal muscle AMPK signaling during exercise: role of AMPKα2 in the regulation of exercise capacity in vivo.
MedLine Citation:
PMID:  21079619     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Objective:Skeletal muscle AMP-activated protein kinase (AMPK)α2 activity is impaired in obese, insulin-resistant individuals during exercise. We determined whether this defect contributes to the metabolic dysregulation and reduced exercise capacity observed in the obese state.Design:C57BL/6J wild-type (WT) mice and/or mice expressing a kinase dead AMPKα2 subunit in skeletal muscle (α2-KD) were fed chow or high-fat (HF) diets from 3 to 16 weeks of age. At 15 weeks, mice performed an exercise stress test to determine exercise capacity. In WT mice, muscle glucose uptake and skeletal muscle AMPKα2 activity was assessed in chronically catheterized mice (carotid artery/jugular vein) at 16 weeks. In a separate study, HF-fed WT and α2-KD mice performed 5 weeks of exercise training (from 15 to 20 weeks of age) to test whether AMPKα2 is necessary to restore work tolerance.Results:HF-fed WT mice had reduced exercise tolerance during an exercise stress test, and an attenuation in muscle glucose uptake and AMPKα2 activity during a single bout of exercise (P<0.05 versus chow). In chow-fed α2-KD mice, running speed and time were impaired ∼45 and ∼55%, respectively (P<0.05 versus WT chow); HF feeding further reduced running time ∼25% (P<0.05 versus α2-KD chow). In response to 5 weeks of exercise training, HF-fed WT and α2-KD mice increased maximum running speed ∼35% (P<0.05 versus pre-training) and maintained body weight at pre-training levels, whereas body weight increased in untrained HF WT and α2-KD mice. Exercise training restored running speed to levels seen in healthy, chow-fed mice.Conclusion:HF feeding impairs AMPKα2 activity in skeletal muscle during exercise in vivo. Although this defect directly contributes to reduced exercise capacity, findings in HF-fed α2-KD mice show that AMPKα2-independent mechanisms are also involved. Importantly, α2-KD mice on a HF-fed diet adapt to regular exercise by increasing exercise tolerance, demonstrating that this adaptation is independent of skeletal muscle AMPKα2 activity.
Authors:
R S Lee-Young; J E Ayala; P T Fueger; W H Mayes; L Kang; D H Wasserman
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Publication Detail:
Type:  Journal Article     Date:  2010-11-16
Journal Detail:
Title:  International journal of obesity (2005)     Volume:  35     ISSN:  1476-5497     ISO Abbreviation:  Int J Obes (Lond)     Publication Date:  2011 Jul 
Date Detail:
Created Date:  2011-07-12     Completed Date:  2011-09-14     Revised Date:  2012-04-20    
Medline Journal Info:
Nlm Unique ID:  101256108     Medline TA:  Int J Obes (Lond)     Country:  England    
Other Details:
Languages:  eng     Pagination:  982-9     Citation Subset:  IM    
Affiliation:
Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA.
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MeSH Terms
Descriptor/Qualifier:
AMP-Activated Protein Kinases / metabolism*
Animals
Dietary Fats / administration & dosage
Exercise Tolerance / physiology
Female
Male
Mice
Mice, Inbred C57BL
Obesity / metabolism*,  physiopathology
Physical Conditioning, Animal / physiology*
Signal Transduction
Grant Support
ID/Acronym/Agency:
R01 DK054902-12/DK/NIDDK NIH HHS; R01 DK054902-13/DK/NIDDK NIH HHS; U24 DK059637-10/DK/NIDDK NIH HHS
Chemical
Reg. No./Substance:
0/Dietary Fats; EC 2.7.11.1/AMP-Activated Protein Kinases; EC 2.7.11.1/AMPK alpha2 subunit, mouse

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


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