Hepatic Catalase Is Not Essential for the Hypolipidemic Action of Peroxisome Proliferators

To evaluate the role of peroxi-somal catalase in lipid metabolism the hypo-lipidemic drugs clofibrate, methyl clofena-pate, and nafenopin were administered to rats in combination with allylisopropylace-tamide, an agent which inhibits catalase synthesis. The number of peroxisomes in liver cells was increased, but these organelles did not contain cytochemically demonstrable catalase. A marked reduction in liver catalase activity was also noted. Although the proliferated peroxisomes were deficient in catalase activity, a substantial hypolipidemic effect was observed in these animals, suggesting that peroxisome catalase is not necessary for the hypolipidemic effect. The increase in carnitine acetyltransferase activity in these animals emphasizes the need to delineate other peroxisomal enzymes which may be involved in lipid metabolism.