The effect of bezafibrate and long-chain fatty acids on peroxisomal activities in cultured rat hepatocytes

Peroxisomal activities have been evaluated in cultured rat hepatocytes in the presence of bezafibrate or long-chain fatty acids added to the culture medium. All activities decreased continuously over a time period of 100 h in culture but selected activities were relatively increased as a function of the added effectors. This relative increase in peroxisomal activities was dose-dependent, discernible within the first 24 h in culture and consisted of activities related specifically to peroxisomal fatty acyl β-oxidation, e.g., cyanide-insensitive palmitoyl-CoA oxidation, H₂O₂-forming palmitoyl-CoA oxidase and heat-labile enoyl-CoA hydratase. Peroxisomal catalase or mitochondrial fatty acyl β-oxidation (cyanide-sensitive) remained relatively unchanged. The relative increase in peroxisomal activities was accompanied by a respective increase in the number of peroxisomes as well as in thymidine incorporation rate.