CETABEN AND FIBRATES BOTH INFLUENCE THE ACTIVITIES OF PEROXISOMAL ENZYMES IN DIFFERENT WAYS

The effects of cetaben and clofibric acid compared on the activities o f peroxisomal enzymes in the liver and kidney of male Wistar rats. Cet aben at 200 mg/kg body wt increased the activities of all of the enzym es in the liver that were studied two to eight times, whereas the chan ges induced by the same dose of clofibric acid increased some of the e nzymes and decreased others. In the kidney, certain increased the acti vities of all of the enzymes in the liver that were studied two to eig ht times, whereas the changes induced by the same dose of clofibric ac id increased some of the enzymes and decreased others. In the kidney, cetaben increased the activities of all investigated peroxisomal enzym es, while clofibric acid only increased the activity of palmitoyl-CoA oxidase. The data obtained in the dose-response study of cetaben revea led a significant rise in the activities of peroxisomal enzymes in bot h the liver and kidney at doses of 50-100 mg/kg body wt administered o ver 10 days, but the maximal effect was observed at 250 mg/kg. Palmito yl-CoA oxidase and D-amino acid oxidase respond most markedly to cetab en. Cetaben could represent an atypical peroxisomal proliferator, sinc e it increased the activities of all peroxisomal enzymes investigated. The fact that the individual components localized in the peroxisomes do not change markedly could be of importance with respect to the func tion and physical properties of peroxisomes.