Alcohols selectively stimulate phospholipase D-mediated hydrolysis of phosphatidylethanolamine in NIH 3T3 cells

Addition of alcohols to NIH 3T3 fibroblasts, prelabeled with [2-14C]ethanolamine, resulted in increased degradation of [14C]phosphatidylethanolamine (PtdEtn). Long-chain alcohols, like octanol or nonanol, were more potent than methanol or ethanol. The main water-soluble product of alcohol-stimulated [14C]PtdEtn hydrolysis was [14C]ethanolamine. Addition of ethanol to cells, specifically prelabeled with [32P]PtdEtn, enhanced the formation of [32P]phosphatidic acid (PtdOH), suggesting the involvement of a phospholipase D-type enzyme. At lower concentration (10-150 mM), ethanol acted through a protein kinase C (PKC)-independent mechanism. At higher concentrations (150-300 mM), the effect of ethanol was partially inhibited both by the PKC inhibitor H7 and by the down-regulation of PKC achieved by treatment of cells with 200 nM TPA for 24 h, suggesting that activation of PKC contributed to the ethanol effect.