Document Detail


Enhanced pyruvate dehydrogenase activity does not affect muscle O2 uptake at onset of intense exercise in humans.
MedLine Citation:
PMID:  11742848     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
It has been proposed that the activation state of pyruvate dehydrogenase (PDH) may influence the rate of skeletal muscle O2 uptake during the initial phase of exercise; however, this has not been directly tested in humans. To remedy this, we used dichloroacetate (DCA) infusion to increase the active form of PDH (PDH(a)) and, subsequently, measured leg O2 uptake and markers of anaerobic ATP provision during conditions of intense dynamic exercise, when the rate of muscle O2 uptake would be very high. Six subjects performed brief bouts of one-legged knee-extensor exercise at approximately 110% of thigh peak O2 uptake (65.3 +/- 3.7 W) on several occasions: under noninfused control (Con) and DCA-supplemented conditions. Needle biopsy samples from the vastus lateralis muscle were obtained at rest and after 5 s, 15 s, and 3 min of exercise during both experimental conditions. In addition, thigh blood flow and femoral arteriovenous differences for O2 and lactate were measured repeatedly during the 3-min work bouts (Con and DCA) to calculate thigh O2 uptake and lactate release. After DCA administration, PDH(a) was four- to eightfold higher (P < 0.05) than Con at rest, and PDH(a) remained approximately 130% and 100% higher (P < 0.05) after 5 and 15 s of exercise, respectively. There was no difference between trials after 3 min. Despite the marked difference in PDH(a) between trials at rest and during the initial phase of exercise, thigh O2 uptake was the same. In addition, muscle phosphocreatine utilization and lactate production were similar after 5 s, 15 s, and 3 min of exercise in DCA and Con. The present findings demonstrate that increasing PDH(a) does not alter muscle O2 uptake and anaerobic ATP provision during the initial phase of intense dynamic knee-extensor exercise in humans.
Authors:
Jens Bangsbo; Martin J Gibala; Peter Krustrup; José González-Alonso; Bengt Saltin
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  282     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2002 Jan 
Date Detail:
Created Date:  2001-12-14     Completed Date:  2002-01-16     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R273-80     Citation Subset:  IM    
Affiliation:
Copenhagen Muscle Research Centre, Institute of Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark. jbangsbo@aki.ku.dk
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MeSH Terms
Descriptor/Qualifier:
Adult
Dichloroacetate / administration & dosage
Enzyme Activation / drug effects
Humans
Lactic Acid / biosynthesis,  metabolism
Male
Muscle, Skeletal / blood supply,  enzymology*
Oxygen / pharmacokinetics*
Oxygen Consumption / physiology
Phosphocreatine / metabolism
Physical Exertion / physiology*
Pyruvate Dehydrogenase Complex / metabolism*
Pyruvic Acid / metabolism
Regional Blood Flow / physiology
Thigh
Chemical
Reg. No./Substance:
0/Pyruvate Dehydrogenase Complex; 127-17-3/Pyruvic Acid; 13425-80-4/Dichloroacetate; 50-21-5/Lactic Acid; 67-07-2/Phosphocreatine; 7782-44-7/Oxygen

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


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