Document Detail


Non-exercising muscle metabolism during exercise.
MedLine Citation:
PMID:  1876479     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Glycogen decrements have been observed in non-exercising muscles during exercise. We therefore investigated whether the degraded glycogen was retained within the muscle in the form of glycolytic intermediates, or whether it was effluxed from the non-exercising muscles. For these studies a suspension harness was used to unload the hindlimb muscles at rest and during exercise [McDermott et al. (1987) J Appl Physiol 63:1275-1283]. Concentrations of glycogen and glycolytic intermediates glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-bisphosphate, glycerol 3-phosphate, and lactate) were measured in non-exercising and exercising muscles (soleus, plantaris, red and white gastrocnemius) during a 90-min exercise about 15 m/min, 8% grade). On-line electromyographic analysis showed that the contractile activity in the non-exercising muscles was markedly lower than in the exercising muscles. Similar decrements in muscle glycogen levels were observed in both the non-exercising and exercising muscles at the end of the 90-min, exercise bout (P less than 0.05), despite significantly different activity profiles. An increase in tissue lactate concentrations occurred in both non-exercising and exercising muscle (P less than 0.05), although only slight changes in the glycolytic intermediates occurred. The sum total of all the accumulated glycolytic intermediates and lactate (converted to glucosyl units) in the non-exercising muscles only accounted for a small fraction of the glycogen degraded (approximately 15%-28%). We conclude that the metabolism of glycogen is enhanced in non-exercising muscle, and that glycogen utilization is uncoupled from the energetic demands of the muscle. Furthermore, the glycogen mobilized in non-exercising muscle is not retained within the muscle in other metabolite pools.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
J C McDermott; G C Elder; A Bonen
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Pflügers Archiv : European journal of physiology     Volume:  418     ISSN:  0031-6768     ISO Abbreviation:  Pflugers Arch.     Publication Date:  1991 May 
Date Detail:
Created Date:  1991-09-26     Completed Date:  1991-09-26     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0154720     Medline TA:  Pflugers Arch     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  301-7     Citation Subset:  IM; S    
Affiliation:
Department of Physiology and Biophysics, Dalhouse University, Halifax, Nova Scotia, Canada.
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / physiology
Animals
Energy Metabolism / physiology
Glycogen / metabolism
Lactates / metabolism
Male
Motor Activity / physiology
Muscles / innervation,  metabolism*,  physiology
Physical Conditioning, Animal*
Rats
Rats, Inbred Strains
Chemical
Reg. No./Substance:
0/Lactates; 9005-79-2/Glycogen

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