Document Detail


Control of glycolysis in contracting skeletal muscle. I. Turning it on.
MedLine Citation:
PMID:  11739085     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Why does the onset of glycolytic flux in muscle lag the start of exercise? We tested the hypothesis that both elevated metabolite levels and muscle activity are required for flux to begin. Glycolytic flux was determined from changes in muscle pH, phosphocreatine concentration, and P(i) concentration ([P(i)]) as measured by 31P magnetic resonance spectroscopy. Eight subjects performed rapid ankle dorsiflexions to approximately 45% of maximal voluntary contraction force under ischemia at a rate of 1 contraction/s. Subjects completed two bouts of exercise separated by 1 min of ischemic rest. Glycolytic flux was activated by 27 s in the first bout, ceased during the ischemic rest period, and was activated more quickly in the second bout. Because the onset in both bouts occurred at approximately the same [P(i)], ADP concentration, and AMP concentration, the activation of glycolysis appears to be related to the elevation of these metabolite concentrations. However, because no glycolytic flux occurred at rest, even when metabolite levels were high, both muscle activity and elevated metabolites are needed to turn on this pathway. We conclude that the delayed onset of glycolytic flux during exercise reflects the time needed to raise metabolites to flux-activating levels.
Authors:
Gregory J Crowther; Michael F Carey; William F Kemper; Kevin E Conley
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  282     ISSN:  0193-1849     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2002 Jan 
Date Detail:
Created Date:  2001-12-12     Completed Date:  2002-01-16     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E67-73     Citation Subset:  IM; S    
Affiliation:
Department of Physiology and Biophysics, University of Washington Medical Center, Seattle, Washington 98195-7115, USA.
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MeSH Terms
Descriptor/Qualifier:
Adenosine Triphosphate / metabolism
Adult
Exercise / physiology
Glycogen / metabolism
Glycolysis / physiology*
Humans
Magnetic Resonance Spectroscopy
Male
Middle Aged
Muscle Contraction / physiology*
Muscle, Skeletal / physiology*
Phosphocreatine / metabolism
Phosphorus / metabolism
Grant Support
ID/Acronym/Agency:
AR-41928/AR/NIAMS NIH HHS; AR-45184/AR/NIAMS NIH HHS
Chemical
Reg. No./Substance:
56-65-5/Adenosine Triphosphate; 67-07-2/Phosphocreatine; 7723-14-0/Phosphorus; 9005-79-2/Glycogen

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


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