Esterification Reaction Affecting the Pattern of Mono-Unsaturated Fatty Acids in Rat Liver

Abstract

Desaturation in vitro of palmitic acid by a postmitochondrial supernatant of rat liver homogenates proceeded about 3 times faster than that of stearic acid. When mitochondria and carnitine were added to the system 15min after the start of incubation, palmitoleic acid produced from palmitic acid decreased more rapidly than oleic acid from stearic acid. However, the rate of oxidation of exogenous palmitoleic acid by isolated mitochondria was about the same with that of exogenous oleic acid. Incorporation of oleic acid into esterified lipids by the postmitochondrial supernatant was about 2 times faster than that of palmitoleic acid, and the release of palmitoleic acid from esterified lipids seemed to be more rapid than that of oleic acid. These findings suggested that the discrepancy between the efficiency of desaturation of the two saturated acids in vitro and the ratio of the two mono-unsaturated acids found in vivo was due to the difference in the rates of incorporation of the two unsaturated acids into esterified lipids.