1. Clofibrate elevates enzyme activities of the tricarboxylic acid cycle in rat liver.
- Author
-
Prager C, Schön HJ, Nikfardjam M, Schmid D, Untersalmberger M, Kremser K, and Kramar R
- Subjects
- Animals, Citrate (si)-Synthase metabolism, Fumarate Hydratase metabolism, Isocitrate Dehydrogenase metabolism, Ketoglutarate Dehydrogenase Complex metabolism, Liver drug effects, Liver ultrastructure, Malate Dehydrogenase metabolism, Male, Rats, Rats, Sprague-Dawley, Subcellular Fractions enzymology, Citric Acid Cycle, Clofibrate pharmacology, Liver enzymology
- Abstract
Activities of the tricarboxylic acid cycle enzymes were measured in subcellular fractions of liver from rats that had been fed clofibrate for 3 weeks. Large changes in these activities per gram tissue were found in the large particle fraction, which also showed an increase in total protein concentration of 76% under clofibrate treatment. The three regulatory enzymes of the cycle, namely citrate synthase, NAD(+)-linked isocitrate dehydrogenase, and 2-oxoglutarate dehydrogenase were significantly enhanced by 24% (P < 0.02), 54% (P < 0.02), and 153% (P < 0.005), respectively. Fumarase and malate dehydrogenase rose by 71% (P < 0.005) and 95% (P < 0.02), whereas succinate dehydrogenase remained unchanged. Enhancement of the citrate synthase, NAD-isocitrate dehydrogenase, and 2-oxoglutarate dehydrogenase may play a role in decreasing intracellular availability of acetyl-CoA for lipid metabolism.
- Published
- 1993