Phosphatidylethanol mimics ethanol modulation of p42/44 mitogen-activated protein kinase signalling in hepatocytes

Aims: Although long-term exposure of hepatocytes to ethanol results in agonist-selective potentiation of p42/44 mitogen-activated protein kinase (MAPK) activation, mediators of this effect of ethanol are not known. Methods: We examined the role of phosphatidylethanol (PEth), a novel phospholipid formed exclusively in the presence of ethanol. Results: PEth accumulated in primary cultures of rat hepatocytes treated with ethanol. Exogenously added PEth potentiated angiotensin II-stimulated p42/44 MAPK similarly to that observed with ethanol treatment of cells for 24 h, a condition where PEth accumulates. PEth levels remained elevated 2 h after ethanol removal subsequent to a 24-h exposure, and the potentiating effects of ethanol were also present. PEth did not potentiate p42/44 MAPK activation by either epidermal growth factor or vasopressin, thus further mimicking the known agonist selectivity for this ethanol effect. Conclusions: These results offer a novel role for PEth as a mediator in the ethanol modulation of p42/44 MAPK cascade in hepatocytes.