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Hepatic Phosphatidylethanolamine Methyltransferase Activity Is Decreased by Ethanol and Increased by Phosphatidylcholine
Author(s) -
Lieber C. S.,
Robins S. J.,
Leo M. A.
Publication year - 1994
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.1994.tb00915.x
Subject(s) - phosphatidylethanolamine , phosphatidylcholine , phospholipid , chemistry , biochemistry , choline , membrane
Phosphatidylethanolamine N‐methyltransferase participates in the synthesis of membrane phosphatidylcholine. Its activity was reported to be decreased in patients with alcoholic cirrhosis, but it is not known whether this is a consequence of the cirrhosis or precedes it. This question was studied in a baboon model of alcohol‐induced fibrosis. Phosphatidylethanolamine N‐methyltransferase activity was measured in sequential percutaneous needle liver biopsies by the conversion of phosphatidylethanolamine to phosphatidylcholine, using radioactive S‐adenosylmethionine as a methyl donor. Chronic alcohol consumption (1–6 years) significantly decreased hepatic phospholipid and phosphatidylcholine levels and reduced phosphatidyl‐ethanolamine N‐methyltransferase activity even before the development of fibrosis. These effects were prevented or attenuated by supplementing the diet with 2.8 g/1000 kcal of a preparation rich in dilinoleoyl phosphatidylcholine, a highly bioavailable phosphatidylcholine species. There were significant ( p < 0.001) correlations between phosphatidylethanolamine N‐methyltransferase activity and both hepatic phosphatidylcholine ( r = 0.678) and total phospholipid ( r = 0.662). Conclusions:1 Alcohol consumption diminishes phosphatidylethanolamine N‐methyltransferase activity prior to the development of cirrhosis and decreases the hepatic content of its product, namely phosphatidylcholine, a key component of cell membranes. This may promote hepatic injury and possibly trigger fibrosis. 2 Phosphatidylcholine administration ameliorates the ethanol‐induced decrease in phosphatidylethanolamine N‐methyltransferase activity and corrects phospholipid and phosphatidylcholine depletions, thereby possibly contributing to the protection against alcoholic liver injury.