Inhibition of myocardial lipase by palmityl CoA

The lipase activity of the adult rat heart consists of at least two components; a lipoprotein lipase and a "hormone-sensitive" or triglyceride lipase. The control of the triglyceride lipase by intermediates of lipid metabolism was studied in rat heart homogenates. Perfusion of hearts with fatty acids, glucose or no exogenous substrate did not alter lipase activity. Bovine serum albumin (BSA) stimulated the in vitro lipase activity whereas palmityl-coenzyme A (CoA) was a potent inhibitor. Other fatty acid intermediates such as acetyl-CoA, acetyl-carnitine, palmityl-carnitine and palmitate had little or no effect. Long-chain acyl CoA may be an important intermediate for matching triglyceride hydrolysis with the supply of extracellular fatty acids and the rates of fatty acid oxidation.