Abstract
The profile of the changes in the peroxisomal fatty acid oxidation activity in rat liver was compared with that in microsomal ω-oxidation under various conditions such as a 2-week administration of phenoxyacetic acid derivatives and perfluorinated compounds, short and long-term administration of clofibrate and bezafibrate, high-fat diet feeding, starvation and diabetes. The results were summarized as follows : 1) when phenoxyacetic acid derivatives and perfluorinated compounds were administered, there was a significant correlation in the increase of the activities between peroxisomal fatty acid oxidation and microsomal ω-oxidation. 2) On the long-term adiministration (79 weeks) of peroxisome proliferators the activities of the enzymes were significantly reduced, but the levels were still higher than the control level in a similar manner. 3) On high-fat diet feeding the patterns of the changes in the activaties of peroxisomal fatty acid oxidation, carnitine acetyltransferase and microsomal ω-oxidation were similar to each other, differing from the changes in the activities of microsomal aminopyrin demethylase and mitochondrial carnitine palmitoyltransferase. 4) Under starved and diabetic conditions, co-induction of peroxisomal fatty acid oxidation and microsomal ω-oxidation was observed. From these results it is suggested that 1) the biosynthesis of these enzymes would be regulated on the gene expression of the nearby domain and 2) peroxisomal fatty acid oxidation and microsomal ω-oxidation were co-operatively regulated in order to achieve fatty acid metabolism smoothly.
