Possible role of hepatic bile mucus glycoprotein in development of intrahepatic gallstones

To study the role played by hepatic bile mucus glycoprotein in the development of hepatolithiasis, mucus glycoprotein, isolated from the bile of patients with intrahepatic gallstones by gel filtration and ultracentrifugation, was examined for precipitability in control hepatic bile obtained postoperatively from patients successfully treated for cholecysto- and/or choledocho-lithiasis. When the mucus glycoprotein was incubated at 38 degrees C for 48 h in the control hepatic bile in the presence of calcium ions, massive precipitation was produced. The precipitation was inhibited by treating the mucus glycoprotein with acid, alkali, a reducing reagent, or protease, the inhibition being most effective with acid, which splits up carbohydrate chains. This suggests that the precipitability of the mucus glycoprotein resides mainly in its carbohydrate chains. These observations imply that the development of intrahepatic gallstones, calcium bilirubinate stones in particular, could be prevented by degrading mucus glycoprotein in hepatic bile.