Document Detail


Skeletal muscle pyruvate dehydrogenase activity during acetate infusion in humans.
MedLine Citation:
PMID:  7762627     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Pyruvate dehydrogenase activity (PDHa), acetyl group, and citrate accumulation were examined in human skeletal muscle at rest and during cycling exercise while acetate was infused. Eight subjects received 400 mmol of sodium acetate (Ace) at a constant rate during 20 min of rest, 5 min of cycling at 40% maximal O2 uptake (VO2max) and 15 min of cycling at 80% VO2max. Two weeks later experiments were repeated while 400 mmol of sodium bicarbonate was infused in the control condition (CON). Ace infusion increased muscle acetyl-coenzyme A (acetyl-CoA), citrate, and acetylcarnitine. A decline in resting PDHa during 20 min of Ace infusion (0.37 +/- 0.08 vs. 0.16 +/- 0.03 mmol.min-1.kg wet wt-1) coincided with an elevation in the acetyl-CoA-to-free CoA ratio (acetyl-CoA/CoASH; 0.28 +/- 0.04 to 0.73 +/- 0.14). After 20 min of CON infusion, resting PDHa (0.32 +/- 0.06 mmol.min-1.kg wet wt-1) was similar to PDHa before Ace infusion. During exercise, acetyl-CoA, citrate, and acetyl-CoA/CoASH were further elevated, and the differences that existed at rest were resolved. PDHa increased to the same extent in Ace and CON, in which it was 44-47% transformed after 5 min at 40% VO2max and completely transformed after 15 min at 80% VO2max. At rest PDHa was regulated by variations in acetyl-CoA/CoASH secondary to enhanced acetate metabolism. Conversely, during exercise PDHa regulation appeared independent of variations in acetyl-CoA/CoASH. The resting data are consistent with a central role for PDHa and citrate in the regulation of the glucose-fatty acid cycle in skeletal muscle, as classically proposed. However, in the present study Ace infusion was not effective in perturbing the glucose-fatty acid cycle during exercise.
Authors:
C T Putman; L L Spriet; E Hultman; D J Dyck; G J Heigenhauser
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  268     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1995 May 
Date Detail:
Created Date:  1995-06-29     Completed Date:  1995-06-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  E1007-17     Citation Subset:  IM    
Affiliation:
Department of Medicine, McMaster University Medical Centre, Hamilton, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Acetates / blood,  pharmacology*
Acetyl Coenzyme A / metabolism
Adult
Blood / metabolism
Coenzyme A / metabolism
Female
Humans
Hydrogen-Ion Concentration
Infusions, Intravenous
Male
Muscle, Skeletal / metabolism*
Oxygen Consumption
Pyruvate Dehydrogenase Complex / metabolism*
Chemical
Reg. No./Substance:
0/Acetates; 0/Pyruvate Dehydrogenase Complex; 72-89-9/Acetyl Coenzyme A; 85-61-0/Coenzyme A

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


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