Alteration of the acyl chain composition of free fatty acids, acyl coenzyme A and other lipids by dietary polyunsaturated fats.

ABSTRACT

Dietary alterations were used to demonstrate selective handling of fatty acids during their redistribution in vivo. Differences in the mol per cent of individual acyl chains in the non-esterified fatty acid, acyl-coenzyme A and phospholipid fractions reflected a result of relative precursor abundance combined with enzymic selectivities. Selective distributions were observed in the utilization of individual acyl chains between 160 and 180, 181 and 182, and among 203, 204 and 205, 226 by ligase(s), hydrolase(s) and acyl-transferases. The variations in the mol per cent of linoleate present in the acyl-coenzyme A fraction of liver relative to that in the non-esterified fatty acids suggested an in vivo regulation of the level of linoleoyl-coenzyme A that influenced the synthesis of both arachidonoyl-coenzyme A and lipids. The greater abundance of eicosapentaenoic acid in the free fatty acid fraction relative to that in the acyl-coenzyme A fraction may increase the ability of dietary 20 5n-3 to be an effective inhibitor of the synthesis of prostaglandins derived from 204n-6.