EFFECTS OF ETHANOL INGESTION AND CHOLINE DEFICIENCY ON HEPATIC LECITHIN BIOSYNTHESIS IN RAT

The effects of long-term ethanol ingestion and choline deficiency on hepatic lecithin metabolism in the rat are described. Rats were given 20% ethanol in drinking water for 1 month to 1 year and changes compared to an isocalorically fed control group. Choline-deficient diets were fed for 4 weeks and results compared with a control group fed the same diet supplemented with 0.5% choline. 1. 1. Chronic ethanol ingestion resulted in a significant (10-15%) increase in hepatic total phospholipid content. An increased content of phospholipid in relation to protein was noted in the isolated microsomal fraction. An increase in both lecithin and phosphatidyl ethanolamine occurred. Triglyceride content was unchanged. 2. 2 An increase in lecithin synthesis by the sequential methylation pathway was noted in homogenates and microsomal fractions prepared from ethanol-treated rats. No changes in the CDP-choline pathway of lecithin synthesis or in triglyceride synthesis were observed. 3. 3. Choline deficiency resulted in a similar increased capacity for lecithin synthesis by sequential methylation without change in the CDP-choline pathway. However, hepatic content of total phospholipid and lecithin fell and triglyceride increased in the choline-deficient rats. Triglyceride synthesis was increased. 4. 4. Supplementation of the diet with 2% choline completely prevented changes in lecithin biosynthesis in the rats given ethanol and partially reversed the increase in phospholipid content. It is concluded that only one pathway of lecithin synthesis de novo is responsive to changes in dietary choline and to the administration of ethanol. Choline in large amounts prevents or decreases ethanol-induced changes in phospholipid metabolism. © 1969.