Lymphatic transport of bile acids in man

The possibility of a lymphatic transport of bile acids in man was investigated. Four patients were studied 2-4 weeks after renal transplantation. As a part of the postoperative immunosuppressive treatment they all had a thoracic duct fistula for lymphatic drainage. After a standardized meal, lymph and peripheral blood samples were simultaneously collected at 30-minute intervals for 210 minutes. The bile acids, cholic acid, chenodeoxycholic acid, and deoxycholic acid were assayed by a gas-liquid chromatography-mass spectrometry method using deuterium-labeled internal standards. The concentration of cholic acid was about the same in lymph and serum. The concentrations of chenodeoxycholic and deoxycholic acids were 2-3 times higher in lymph than in serum, both in the fasting state and postprandially. These results are explained by a more efficient passive absorption of the less polar dihydroxy bile acids. The transport of bile acids in the lymph was calculated to be only about 0.2% of that in the portal vein.