Differential Quantitative Analysis of Bile Acids in Bile and in Duodenal Drainage

By the combination of 3 different methods the analysis of bile for taurocholic acid, glycocholic acid, total conjugated bile acids, cholic acid, deoxycholic acid, total bile acids, and free bile acids has been achieved. It has also been possible to analyze duodenal drainage material for cholic acid, deoxycholic acid and total bile acids.

Methods. 1. The Cuny 1 modification of the Schmidt-Dart 2 method is used to determine the taurine and glycine nitrogen percentage. The first is multiplied by 33.87 and the second by 28.29 to give the bile acids conjugated with taurine and with glycine. The sum of these 2 figures gives the total bile acids that are conjugated. 2. Cholic acid is determined by a method outlined in the previous paper. 3 3. The total bile acids are estimated by an iron precipitation method based partly on principles devised by Harwood. 4 After the bile acids have been extracted and made up to 100 cc. in a volumetric flask and the cholic acid determined, the amount of solution in the volumetric flask, estimated to contain between 40-60 mg. of bile acids, is measured out into a 150 cc. beaker. This calculation is derived from the known amount of cholic acid present in the volumetric flask. The bile acids of dog bile may be considered to be approximately 100% cholic acid, while those of human bile can be assumed to be 50% cholic acid. Thus if the volumetric flask is found to contain 100 mg. cholic acid derived from dog bile, 50 cc. of the solution is measured in the beaker. If the extract is derived from human bile, only 25 cc. is taken.