Coordinate Suppression of Liver Acetyl-CoA Carboxylase and Fatty Acid Synthetase by Polyunsaturated Fat

Publisher Website
Google Scholar
Abstract
Polyunsaturated fats (PUFA) suppressed hepatic fatty acid synthesis and the activities of lipogenic enzymes more effectively than did saturated fats. The activity of glycolytic enzymes—glucokinase, phosphofructokinase and pyruvate kinase—were not affected by PUFA. The absolute rate of liver fatty acid synthesis after meal ingestion was very similar to the maximal activities of acetyl-CoA carboxylase and fatty acid synthetase. When PUFA was supplemented to a fat-free diet, the activities of carboxylase and synthetase decreased similarly over 3 days. During the 3 days, the concentration of liver malonyl-CoA (after meal ingestion) did not significantly differ between the fat-free and PUFA dietary treatments. Apparently PUFA feeding caused a coordinate decrease in the utilization and production of malonyl-CoA which resulted in no net change in malonyl-CoA pool size. Thus the mechanism by which PUFA suppresses fatty acid synthesis appears to be by coordinately and specifically reducing the amount of carboxylase and fatty acid synthetase.