Bilirubin UDP-glucuronyl transferase (GT) activity in the liver and small intestine of ten patients was examined. In five of the ten patients, GT activity was examined systematically in various tissues including the liver, kidney, spleen, stomach, duodenum, jejunum, ileum, and ascending and sigmoid colon. GT activity was detected not only in the liver but also in the small intestinal mucosa, especially in the jejunum. No detectable activity was found in the other tissues examined. The enzyme kinetics indicated that the GT in the liver and the GT in the small intestine were the same enzyme. GT activity in both the liver and small intestine was more effectively activated with the cationic detergent cetyltrimethylammonium bromide than digitonin, that has usually been employed. This activation was not affected by jaundice. Small intestinal GT activity in the five patients with hepatocellular jaundice was generally higher than that in the two patients with obstructive jaundice and the three nonicteric patients.
Bilirubin UDP-glucuronyl transferase
Human intestinal mucosa
Cetyltrimethylammonium bromide (CTAB)