Phospholipid transmethylation and choline phosphotransferase in microsomal fraction of human diseased liver.

The activities of three enzymes catalyzing the production or degradation of phosphatidylcholine, a major structural phospholipid of cell membranes, were assessed in hepatocyte membrane microsomal preparation from patients with various types of liver disease. Choline phosphotransferase activity of preparation from patients with chronic aggressive, chronic active, chronic persistent, alcoholic hepatitis and cirrhosis accompanied by marked necrosis and relatively slight fibrosis was markedly decreased, compared with normal liver; the activity from patients with fatty liver and chronic inactive hepatitis was slightly decreased. Specimens from patients with acute transient hepatitis were not significantly different from normal. Methyltransferase and phospholipase A2 activities tended to parallel that of choline phosphotransferase, although the degree of changes was generally less marked. Our studies indicate that enzyme activities that are critical for hepatic cell membrane integrity and activity are attenuated in liver specimens from patients with disease in which there is marked hepatic cell necrosis.