Inhibition of the hormone-sensitive lipase in adipose tissue by long-chain fatty acyl coenzyme A.

The effects of free fatty acids and fatty acyl esters of coenzyme A and carnitine on the activity of a hormone-sensitive lipase preparation made from pigeon adipose tissue were determined. Oleic acid (100 microM) resulted in a 40% inhibition of lipase activity. A more potent inhibition of lipase activity was seen with long-chain fatty acyl CoA compounds. The concentration required for half-maximal inhibition with oleoyl CoA and palmitoyl CoA was 25-40 microM, whereas palmitoyl carnitine stimulated lipase activity. Activated lipase preparations (preincubated with Mg2+, ATP, cyclic AMP and protein kinase) were 4-6 times more sensitive to inhibition by oleoyl CoA than were nonactivated preparations. An increase in cellular levels of fatty acyl coenzyme A could, therefore, contribute to the feedback inhibition of lipolysis in adipose tissue.