Intestinal Absorption of Bile Pigments

ESTIMATION of urine urobilinogen is widely used as a rapid laboratory method for evaluation of hepatobiliary function and the production of bile pigment. Interpretation of the results is based on the concept of a functioning enterohepatic circulation of urobilinogens that are formed by bacterial reduction of bilirubin in the large bowel (Fig. 1). Although this concept is generally accepted, largely as a result of the classic studies by Watson,1 direct demonstration of intestinal absorption and re-excretion of urobilinogen has not heretofore been possible. The methodologic difficulties inherent in this problem have now been circumvented by the preparation of an isotopically . . .