Increases in liver microsomal phosphatidylethanolamine methyltransferase activity(s) in mice after short-term ethanol treatments.

Adult C57/BL mice subjected to short term ethanol liquid diets exhibited significant increases in liver microsomal phosphatidylethanolamine methyltransferase activity(s) as well as changes in microsomal lipid composition. Specifically, increases in [3H]-methyl incorporation into phosphatidyl-N-monomethylethanolamine and phosphatidyl-N,N-dimethylethanolamine were observed suggesting increases in phospholipid methyltransferase I and the first methyl transfer reaction of phospholipid methyltransferase II. Labeling of phosphatidylcholine was not affected, however. Dietary supplementation with 2% choline reduced liver methyltransferase activities of both control and ethanol treated mice. The ethanol induced increase in methyltransferase activity returned to control values upon removal of ethanol from the diet for 24 hours. It is suggested that the increase in phospholipid methyltransferase activity after chronic ethanol treatment may be responsible, in part, for alterations in the activities of certain microsomal enzymes known to be influenced by ethanol.