Effect of clofibrate feeding on palmitate and branched-chain 2-oxo acid oxidation in rat liver and muscle.
Oxidation rates of palmitate (total and antimycin-insensitive), pyruvate, leucine, 4-methyl-2-oxopentanoate and 3-methyl-2-oxobutanoate and activities of two mitochondrial marker enzymes (citrate synthase and cytochrome c oxidase) were assayed in liver and muscle homogenates of fed, clofibrate-treated and 18 hr-starved rats. Significant alterations in the clofibrate-treated and the starved rats were predominantly observed in the liver. Clofibrate feeding increased antimycin-insensitive (peroxisomal) and antimycin-sensitive (mitochondrial) palmitate oxidation and 4-methyl-2-oxopentanoate and pyruvate oxidation in liver. In muscle, only the activities of citrate synthase and cytochrome c oxidase were slightly decreased. Short starvation increased antimycin-sensitive palmitate and 4-methyl-2-oxopentanoate oxidation in liver. The rates of pyruvate and 3-methyl-2-oxobutanoate oxidation were decreased in muscle homogenates. Results suggest that myopathic phenomena observed after chronic clofibrate administration are not related to changes in the capacity of oxidative metabolism of muscle.
D000818:Animals; D002950:Citrate (si)-Synthase / Q000378:metabolism; D002994:Clofibrate / Q000494:pharmacology*; D003576:Electron Transport Complex IV / Q000378:metabolism; D007651:Keto Acids / Q000378:metabolism*; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism*; D011773:Pyruvates / Q000378:metabolism; D019289:Pyruvic Acid; D051381:Rats; D011919:Rats, Inbred Strains
D007651:Keto Acids; D010169:Palmitic Acids; D011773:Pyruvates; D019308:Palmitic Acid; D019289:Pyruvic Acid; D003576:Electron Transport Complex IV; D002950:Citrate (si)-Synthase; D007930:Leucine; D002994:Clofibrate