Bile Acid Metabolism in Mammals. VIII. Biliary Secretion of Cholylarginine by the Isolated Perfused Rat Liver

Abstract

In studies of cholic acid metabolism using the isolated perfused rat liver system, an unknown conjugate of cholic acid was observed. This conjugate comprised 15–27% of the biliary bile acids in these experiments, was less polar than cholylglycine on thin-layer chromatography using butanol, acetic acid, and water, and had an apparent molecular weight greater than that of cholyltaurine on gas–liquid chromatography. Amino acid analysis of the hydrolyzed conjugate demonstrated the presence of arginine. Perfusion studies with radioactive arginine, and mass spectrometric analysis proved that the conjugate was cholylarginine. Secretion of this conjugate does not represent a deficiency of available glycine and taurine.