Nutritional Control of Fatty Acid Esterification in Differentiating Caco-2 Intestinal Cells Is Mediated by Cellular Diacylglycerol Concentrations

The Caco-2 human intestinal cell line was used to investigate the effects of exogenous lipid on fatty acid esterification in differentiating intestinal absorptive cells. Preincubation of Caco-2 cells with either palmitate or palmitate plus 2-monoolein resulted in greater utilization of subsequently added fatty acid for triacylglycerol relative to phosphatidylcholine synthesis. Despite this lipid-induced alteration in metabolism, the activities of acyl-CoA synthetase, glycerol-3-phosphate acyltransferase and diacylglycerol acyltransferase were unchanged. In addition, monoacylglycerol acyltransferase activity was nearly undetectable, even after preincubation with 2-monoolein. The intracellular diacylglycerol concentrations were, however, increased with greater lipid substrate availability. These studies indicate that, under conditions of increased dietary lipid, intestinal fatty acid esterification via the glycerol-3-phosphate pathway is modulated by cellular diacylglycerol concentrations.