3 alpha-, 7 alpha-, and 12 alpha-OH group specific enzymic analysis of biliary bile acids: comparison with gas-liquid chromatograpy

3 alpha-Hydroxysteroid dehydrogenase (3 alpha-HSDH) from P. testosteroni, 7 alpha-HSDH (Escherichia coli ATCC No. 29532) and 12 alpha-HSDH (Clostridium group P, strain C48-50, ATCC No. 29733) were used to directly measure 3 alpha-, 7 alpha-, and 12 alpha-OH groups in extracted human bile-rich duodenal aspirates. Twelve samples chosen from widely differing ratios of cholic/chemodeoxycholic/deoxycholic were computed by solving three simultaneous equations. Comparison of these ratios with those obtained by a) thin-layer chromatography and 3 alpha-, 7 alpha-HSDH assays and b) gas-liquid chromatographic analysis showed no significant difference. Addition of known amounts of pure cholic, chenodeoxycholic, deoxycholic, or lithocholic acid to individual bile extracts gave an appropriate yield of 3 alpha-, 7 alpha-, and 12 alpha-OH groups. The direct (non-chromatographic) enzymic method has the advantages of being rapid, convenient, and inexpensive, and thus suitable for clinical use.