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

Abstract

The capacity of mitochondrial β-oxidation and activities of three acyl-CoA dehydro genases and electron transfer flavoprotein in rat liver were increased after admini stration of peroxisome proliferators such as di(2-ethylhexyl)phthalate or p-chloro phenoxyisobutyrate. Oxygen consumption by mitochondrial β-oxidation with palmitate, palmitoyl-CoA or palmitoylcarnitine was in the range of 0.27–0.41 μmol O₂/min per g liver and the dehydrogenase activity with palmitoyl-CoA was 0.56 μmol/min per g liver. These activities were increased, after administration of peroxisome proliferators, to 0.80–1.23 μmol O₂/min per g liver and 1.06–1.08 μmol/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 halflives of about a day.