Activation of branched-chain α-keto acid dehydrogenase complex by exercise: Effect of high-fat diet intake

Y. Shimomura, T. Suzuki, S. Saitoh, Y. Tasaki, R. A. Harris, M. Suzuki

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Abstract

The effect of exercise on the activity of branched-chain α-keto acid dehydrogenase complex in liver and muscle was studied in rats fed a high-fat (FAT) or a high-carbohydrate (CHO) diet. Both diet groups of rats were offered isoenergetic diets by a meal-feeding method and were trained by treadmill running. On the final day of the experiment, half of the rats in each diet group were exercised by 2 h of running just before they were killed. The activity state of the enzyme complex was elevated maximally by exercise in liver of rats fed the FAT diet but not in liver of rats fed the CHO diet, suggesting that catabolism of branched-chain amino acids in rat liver during exercise was enhanced by the FAT diet. The activity state of the enzyme complex in muscle was enhanced by exercise in both groups of rats, but a significant difference was not observed between the groups. The concentration of branched-chain amino acids was elevated in liver and muscle by exercise in both groups of rats, but the elevated levels in liver were lower in rats fed the FAT diet than in those fed the CHO diet. Serum branced-chain amino acid concentrations were significantly lower in rested rats fed the FAT diet than in those fed the CHO diet, and the leucine and isoleucine concentrations in the former were elevated by exercise, but the serum concentrations in the latter were not significantly affected by exercise. ATP and ADP concentrations in muscle were not significantly affected by either diet or exercise. The mechanism of the activation of branched-chain α-keto acid dehydrogenase complex caused by exercise is discussed in relation to the tissue concentrations of leucine and nucleotides.

Original languageEnglish (US)
Pages (from-to)161-165
Number of pages5
JournalJournal of Applied Physiology
Volume68
Issue number1
StatePublished - Jan 1 1990

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Keywords

  • adenosine 5'-diphosphate
  • adenosine 5'-triphosphate
  • branched-chain amino acids
  • liver
  • muscle
  • rat

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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