Role of biliary phosphatidylcholine in the absorption and transport of dietary triolein in the rat.

This study was undertaken to determine the role of luminal phosphatidylcholine in the intestinal absorption and transport of glycerol trioleate in the rat. Rats with bile and thoracic duct lymph fistulas were infused with a bile salt-stabilized emulsion of glycerol trioleate only or with either dioleoyl or dipalmitoyl phosphatidylcholine added. Uptake of infused lipid was greater than 95% in all groups. The presence of supplemental phosphatidylcholine in the infusate greatly enhanced the lymphatic triglyceride and phosphatidylcholine outputs in the bile-diverted rats as compared with rats without phosphatidylcholine supplementation. There was no difference in lipid outputs between the dioleoyl or dipalmitoyl phosphatidylcholine-supplemented rats. The fatty acid pattern of the lymph phosphatidylcholine of the two groups of phosphatidylcholine-supplemented rats reflected that of the added phosphatidylcholine. In the absence of luminal phosphatidylcholine there was increased accumulation of mucosal triglyceride and evidence suggesting increased portal transport of absorbed fatty acid. Therefore, this study demonstrated that the presence of luminal phosphatidylcholine is important for the normal lymphatic transport of the absorbed digestion products of triglyceride, the major dietary fat.