Induction of Acyl-CoA Dehydrogenases and Electron Transfer Flavoprotein and Their Roles in Fatty Acid Oxidation in Rat Liver Mitochondria1

The capacity of mitochondrial beta-oxidation and activities of three acyl-CoA dehydrogenases and electron transfer flavoprotein in rat liver were increased after administration of peroxisome proliferators such as di(2-ethylhexyl)phthalate or p-chlorophenoxyisobutyrate. Oxygen consumption by mitochondrial beta-oxidation with palmitate, palmitoyl-CoA or palmitoylcarnitine was in the range of 0.27-0.41 mumol O2/min per g liver and the dehydrogenase activity with palmitoyl-CoA was 0.56 mumol/min per g liver. These activities were increased, after administration of peroxisome proliferators, to 0.80-1.23 mumol O2/min per g liver and 1.06-1.08 mumol/min per g liver, respectively. The time required to reach half-maximal induction of the three acyl-CoA dehydrogenases and electron transfer flavoprotein after administration of di(2-ethylhexyl)phthalate was about 5 days. On the withdrawal of the agent, the activities of these flavoproteins decreased to the control levels with half-lives of about a day.