Document Detail


Insulin activation of pyruvate dehydrogenase complex is enhanced by exercise training.
MedLine Citation:
PMID:  10421227     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We studied the effects of exercise training on the activity of the pyruvate dehydrogenase (PDH) complex in rat gastrocnemius muscle (experiment 1) and the response of the complex to glucose and insulin infusion (euglycemic clamp) in trained and sedentary rats (experiment 2). In experiment 1, half of the rats were randomly allocated as sedentary animals and the other half were trained by voluntary running exercise for 8 weeks. The total activity of the PDH complex was not affected by exercise training, and the activity state (proportion of the active form) of the PDH complex was decreased from 15.0%+/-2.4% to 7.5%+/-1.1% by exercise training. The activity of 3-hydroxyacyl-coenzyme A (CoA) dehydrogenase ([3-HADH] an enzyme in beta-oxidation) was significantly higher in trained versus sedentary rats. In experiment 2, sedentary and trained rats were starved for 24 hours before performing the euglycemic clamp. Glucose and insulin infusion was performed by a euglycemic clamp (insulin infusion rate, 6 mU/kg/min) for 90 minutes. The PDH complex was inactivated to less than 1% in both sedentary and trained rats after 24 hours of starvation. The glucose infusion rate (GIR) during the euglycemic clamp was higher in trained versus sedentary rats. The euglycemic clamp resulted in activation of the PDH complex in both sedentary and trained rats, but the response of the PDH complex to the euglycemic clamp was significantly higher in trained rats (5.8%+/-0.5%) than in sedentary rats (2.9%+/-0.5%). These results suggest that exercise training promotes fatty acid oxidation in association with suppression of glucose oxidation in skeletal muscle under resting conditions, but increases the rate of carbohydrate oxidation when glucose flux into muscle cells is stimulated by insulin.
Authors:
N Nakai; Y Sato; Y Oshida; N Fujitsuka; A Yoshimura; Y Shimomura
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Metabolism: clinical and experimental     Volume:  48     ISSN:  0026-0495     ISO Abbreviation:  Metab. Clin. Exp.     Publication Date:  1999 Jul 
Date Detail:
Created Date:  1999-08-03     Completed Date:  1999-08-03     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0375267     Medline TA:  Metabolism     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  865-9     Citation Subset:  IM; S    
Affiliation:
Research Center of Health, Physical Fitness and Sports, Nagoya University, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Enzyme Activation / physiology
Female
Glucose Clamp Technique
Insulin / physiology*
Muscle, Skeletal / enzymology
Physical Conditioning, Animal / physiology*
Protein Kinases / metabolism
Protein-Serine-Threonine Kinases
Pyruvate Dehydrogenase Complex / metabolism*
Rats
Rats, Wistar
Chemical
Reg. No./Substance:
0/Pyruvate Dehydrogenase Complex; 11061-68-0/Insulin; EC 2.7.-/Protein Kinases; EC 2.7.11.1/Protein-Serine-Threonine Kinases; EC 2.7.11.2/pyruvate dehydrogenase (acetyl-transferring) kinase

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