Beta-glucuronidase activity in the bile of gallstone patients both with and without duodenal diverticula

Patients with juxtapapillary duodenal diverticula have an increased occurrence of calcium bilirubinate gallstones. One possible hypothesis to explain this observation is enzymatic deconjugation of bilirubin conjugates in the bile. Beta-glucuronidase of human or bacterial origin may lead to deconjugation of the bilirubin glucuronides in bile. This, in turn, may increase the amounts of unconjugated, water-insoluble bilirubin which can precipitate as calcium bilirubinate, the main component of brown pigment stones. In this study we compared gallstone patients with and without duodenal diverticula treated with endoscopic papillotomy. Increased occurrence of bacteria producing beta-glucuronidase (p less than 0.01) and increased activity of bacterial beta-glucuronidase (pH 7.0) in the bile itself (p less than 0.01) were found in patients with duodenal diverticula. When the activity of the enzyme at pH 4.5, the optimum of the human enzyme, was measured, no such difference was found. The results support the hypothesis of bacterial glucuronidase as an etiologic factor in pigment gallstone disease in patients with duodenal diverticula. The high activity of bacterial enzyme found in the bile in some patients without diverticula suggests bacteria as an etiologic factor, independent of the presence of diverticula.