Studies on the metabolism of unsaturated fatty acids. XI. Alterations in the activities of enoyl-CoA hydratase, 3-hydroxyacyl-CoA epimerase and 2,4-dienyl-CoA reductase in rat liver mitochondria and peroxisomes by clofibrate.

Alterations in the activities of enoyl-CoA hydratase, 3-hydroxyacyl-CoA epimerase, and 2,4-dienoyl-CoA reductase in rat liver mitochondria and peroxisomes caused by clofibrate were compared in order to clarify the metabolic pathways for unsaturated fatty acids. Our results suggest that there are two pathways for fatty acids having (a) double bond(s) at the even-numbered carbon atom(s) both in mitochondria and in peroxisomes. One is the hydratase-epimerase participating pathways, and the other is the reductase participating pathway. It is considered that the former in mitochondria occurs mainly under normal conditions, and the latter becomes significant when the degradation of fatty acids is stimulated.