A Study on the Activity of β-Glucuronidase in Bile in Connection with Precipitation of Calcium Bilirubinate

Abstract

The present authors succeeded in measurement the hitherto unreported activity of [beta]-glucuronidase ([beta]-G) in bile sampled from patients of biliary tract disease, using a modified Fishman''s original method. The [beta]-G activity was negative in bile from control cases without biliary tract diseases, but was found perceptibly intensified in the bile specimens sampled from the gall bladder of nearly all patients of cholelithiasis, either of pigmented calcium stone or cholesterol stone type. When the pH value in the incubation system was gradually raised from 3.8 to 8.1, the activity of [beta]-G in bile containing E. coli sampled from pigmented calcium stone cases or non-calculous cases rose to the highest level near the optimum pH for bacterial [beta]-G (6.6[long dash]7.15), while that in the aseptic bile specimens from cholesterol stone cases attained the maximum near the optimum pH for visceral [beta]-G (4.5[long dash]5.2). Such observations on the optimum pH value for the activity of [beta]-G led to the inference that the activity is chiefly that of the so-called bacterial [beta]-G in the bacteria-containing bile from pigmented caliculi and that of the so-called visceral [beta]-G in the aseptic bile from the cholesterol stone cases. When the activity of [beta]-G, a hydrolase acting on glucuronides in bile, is once accentuated, under certain conditions the bilirubin glucuronide will be hydrolyzed into free bilirubin and glucuronic acid, and theoretically it may be inferred that the carboxyl radical in this free bilirubin is replaced by Ca, thus leading to formation of Ca bilirubinate.