Fecal bile acid analysis in healthy Japanese subjects using a lipophilic anion exchanger, capillary column gas chromatography and mass spectrometry.

Detailed fecal bile acid profiles of healthy Japanese subjects were studied using a lipophilic anion exchanger, capillary gas chromatography and mass spectrometry. Total dairy excretion of bile acid into feces corrected for by fecal markers were between 127.99 to 366.33 mumole per day. Unconjugated bile acids constituted a major part, between 80 and 96%, of fecal bile acids. Glycine conjugated, taurine conjugated and sulfated bile acids were between 1 to 6, 0 to 3 and 1 to 10%, respectively. Esterified bile acids at C-24 position existed between 1 to 5%. Primary bile acids ranged from 0 to 55%. There were a number of epimers of hydroxy- and keto-bile acids, and lithocholic and deoxycholic acid were major secondary bile acids among them. A cholenoic acid was detected in the unconjugated fraction of one subject. It seems necessary to analyze the details not only on the type of bile acids but also on the mode of conjugation in biological samples. Thus, the methodology described in this study has made it easier to investigate on the role of bile acid in the physiology or pathophysiology of the gastrointestinal tract.