Journal of Lipid Research, Vol. 23, 1020-1025, September 1982
Copyright © 1982 by Lipid Research, Inc.

Fasting levels of monoketonic bile acids in human peripheral and portal circulation

Ingemar Björkhem , Bo Angelin , Kurt Einarsson , and Staffan Ewerth

Departments of Clinical Chemistry, Medicine, and Surgery at Huddinge University Hospital, Karolinska Institutet, S-141 86 Huddinge, Sweden

It has been suggested that large amounts of ketonic bile acids may be present in portal venous blood. We have therefore determined the approximate concentration of 3-oxo-, 7-oxo-, and 12-oxo-bile acids (monoketonic bile acids) in human peripheral and portal circulation. These compounds were converted into the corresponding 3-, 7-, and 12-hydroxy bile acids by treatment with sodium borodeuteride, thus increasing the molecular weight of each bile acid formed by one mass unit. The ratio between deuterated and nondeuterated bile acid was determined by combined gas-liquid chromatography-mass spectrometry with use of selected ion monitoring. From the ratio obtained and from the concentration of unlabeled bile acid, determined by isotope dilution-mass spectrometry, the approximate concentration of the different ketonic bile acids could be calculated. This method underestimates 3-oxygenated bile acids by 4-8%, 7-oxygenated bile acids by 2-3%, and 12-oxygenated bile acids by about 25%. The approximate concentration of monoketonic 3,7-oxygenated bile acids was found to be 0.08 ± 0.02 and 0.37 ± 0.25 µmol/l in the peripheral venous serum and the portal venous serum, respectively. The approximate concentration of monoketonic 3,12-oxygenated bile acids was found to be 0.07 ± 0.02 and 0.32 ± 0.12 µmol/l in the peripheral venous serum and the portal venous serum, respectively. The approximate concentration of monoketonic 3,7,12-oxygenated bile acids was found to be 0.03 ± 0.01 and 0.14 ± 0.05 µmol/l in the peripheral venous serum and in the portal venous serum, respectively. The total concentration of the ketonic bile acids constituted only 9 ± 1% and 8 ± 3% of the nonoxidized bile acids in the peripheral venous serum and in the portal venous serum, respectively. Thus it seems less likely that the portal inflow of ketonic bile acids is of significant physiological importance under normal conditions.—Björkhem, I., B. Angelin, K. Einarsson, and S. Ewerth. Fasting levels of monoketonic bile acids in human peripheral and portal circulation.

Supplementary key words serum bile acids • cholic acid • chenodeoxycholic acid • deoxycholic acid • mass fragmentography • portal blood

Submitted on January 4, 1982
Revised on May 4, 1982

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