Document Detail

Control of glycolysis in contracting skeletal muscle. I. Turning it on.
MedLine Citation:
PMID:  11739085     Owner:  NLM     Status:  MEDLINE    
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.
Gregory J Crowther; Michael F Carey; William F Kemper; Kevin E Conley
Related Documents :
25050695 - Hormonal, metabolic and cardiorespiratory responses of young and adult athletes to a si...
1549225 - 31p magnetic resonance spectroscopy suggests impaired mitochondrial function in azt-tre...
1464875 - 31p magnetic resonance spectroscopy of skeletal muscle in patients with fibromyalgia.
864695 - Pulsed nuclear magnetic resonance study of 39k within halobacteria.
18580405 - Trained men display increased basal heat shock protein content of skeletal muscle.
11127455 - Natural progesterone, but not medroxyprogesterone acetate, enhances the beneficial effe...
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    
Department of Physiology and Biophysics, University of Washington Medical Center, Seattle, Washington 98195-7115, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Adenosine Triphosphate / metabolism
Exercise / physiology
Glycogen / metabolism
Glycolysis / physiology*
Magnetic Resonance Spectroscopy
Middle Aged
Muscle Contraction / physiology*
Muscle, Skeletal / physiology*
Phosphocreatine / metabolism
Phosphorus / metabolism
Grant Support
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

Previous Document:  Adipose tissue-specific increase in angiotensinogen expression and secretion in the obese (fa/fa) Zu...
Next Document:  Control of glycolysis in contracting skeletal muscle. II. Turning it off.