Effect of Phosphatidylcholine on Triacylglycerol Synthesis in Rat Intestinal Mucosa

Abstract

The acyltransferases involved in triacylglycerol synthesis were studied in mucosal microsomes from normal and bile fistula rats. Sustained biliary diversion (2–3 days) resulted in a 35–40% decrease in the activities of the mono- and diacylglycerol acyltransferases. In addition, the phospholipid/protein and phosphatidylcholine/phosphatidylethanolamine ratios were lower in the mucosal microsomes from the bile fistula rats. The addition of phosphatidylcholine and lysophosphatidylcholine to the mucosal microsomes resulted in restoration of the enzyme activities to control levels. Unsaturated species of phosphatidylcholine were more effective than saturated species. The phosphatides of ethanolamine, inositol, and serine were without effect. This suggested that the loss in enzyme activity was associated with a depletion of phosphatidylcholine in the mucosal microsomes. It is concluded that the mono- and diacylglycerol acyltransferases require phosphatidylcholine for optimal activity.