Document Detail

Energy sources in fully aerobic rest-work transitions: a new role for glycolysis.
MedLine Citation:
PMID:  4003569     Owner:  NLM     Status:  MEDLINE    
Rate of O2 consumption (VO2), intracellular PO2, lactate extraction, and tissue contents of phosphocreatine, creatine, ATP, lactate, and pyruvate were measured during rest-work transitions in dog gracilis muscles. Samples were taken at rest and after 5, 10, 15, 30, 60, and 180 s of twitch contraction at 4/s. There was no anoxia at any time or location [companion paper, Am. J. Physiol. 248 (Heart Circ. Physiol. 17): H914-H921, 1985]. Energy was supplied by a continuous utilization of phosphocreatine stores, a slow rise in VO2, and two distinct bursts of glycolysis. Glycolytic rate was independent of tissue PO2 and VO2 and was poorly correlated with phosphocreatine under the aerobic conditions of our experiments. The glycolytic bursts served as a source of ATP, and the bulk of the lactate formed remained in the tissue. Lactate efflux was a small fraction of tissue lactate; it depended on blood flow but not on tissue lactate content. At steady state a small glycolytic flux maintained the high tissue lactate mainly by matching rates of pyruvate production and oxidation. We propose that this flux and the high tissue lactate concentration buffer cytosolic redox and/or substrate supply in support of the aerobic functions of mitochondria during exercise.
R J Connett; T E Gayeski; C R Honig
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  248     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1985 Jun 
Date Detail:
Created Date:  1985-07-25     Completed Date:  1985-07-25     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H922-9     Citation Subset:  IM; S    
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MeSH Terms
Adenosine Triphosphate / metabolism
Energy Metabolism*
Lactates / blood
Lactic Acid
Muscles / physiology*
Oxygen Consumption
Physical Exertion*
Pyruvates / blood
Pyruvic Acid
Grant Support
Reg. No./Substance:
0/Lactates; 0/Pyruvates; 127-17-3/Pyruvic Acid; 50-21-5/Lactic Acid; 56-65-5/Adenosine Triphosphate

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

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