The effect of methyl-lidocaine on the biosynthesis of phospholipids de novo in the isolated hamster heart.

Methyl-lidocaine is an amphiphilic agent which has been used as an experimental anti-arrhythmic drug. When hamster hearts were perfused with labelled glycerol, the presence of methyl-lidocaine in the perfusate was found to enhance the labelling in phosphatidylserine, phosphatidylinositol, diacylglycerol and triacylglycerol. However, the labelling of phosphatidylcholine and phosphatidylethanolamine was not significantly changed by methyl-lidocaine treatment. Assays in vitro for the enzymes involved in the synthesis of neutral lipids and acidic phospholipids revealed that phosphatidate phosphatase and CTP: phosphatidate cytidylyltransferase activities were stimulated by methyl-lidocaine. The intracellular pool sizes of diacylglycerol and CDP-diacylglycerol were also elevated. We postulate that the enhanced syntheses of the neutral lipids and acidic phospholipids in the methyl-lidocaine-perfused heart were mediated via the direct activation of the key enzymes in the biosynthesis of these lipids de novo.