EFFECT OF CLOFIBRATE AND HIGH-FAT DIET ON AMINOTRANSFERASE ACTIVITY IN RAT-LIVER

The effects of clofibrate, high-fat diet and both clofibrate and high-fat diet on aminotransferase activities were studied in rat liver. The studied enzymes included phenylalanine-glyoxylate, alanine-glyoxylate, aspartate-2-oxoglutarate, alanine-2-oxoglutarate and tyrosine-2-oxoglutarate aminotransferases. Clofibrate induced an 89% increase in phenylalanine-glyoxylate aminotransferase activity. In the case of alanine-glyoxylate aminotransferase, however, the result was a decrease in enzyme activity by 28%. In the other enzymes studied, clofibrate did not produce marked changes. The high-fat diet resulted in decreased total activities in all aminotransferases studied; the most pronounced decline of 34% was found in alanine-2-oxoglutarate aminotransferase. The simultaneous administration of clofibrate and high-fat diet produced an increase in phenylalanine-glyoxylate aminotransferase activity by 36% and a decrease in alanine-glyoxylate aminotransferase and alanine-2-oxoglutarate aminotransferase activities by 23 and 42%, respectively. Also studied were changes in aminotransferase subcellular distribution induced by separate administration of clofibrate and of a high-fat diet. Clofibrate apparently substantially affects not only lipid, but also protein and amino acid metabolism, namely by stimulating degradation of these compounds.