[Role of bile glycoprotein in intrahepatic calculus formation]

To clarify the etiology of intrahepatic calculus formation, we examined the components of hepatic bile, particularly glycoprotein, in 20 controls and 10 patients with intrahepatic calculi. The results obtained were summarized as follows: 1) The yield of delipidized bile powder was approximately 2.5 times higher in intrahepatic calculosis than in control. Quantitative analysis revealed that protein and neutral sugar were significantly increased in intrahepatic calculosis as compared with those in control. In SDS-PAGE of the powder, both intrahepatic calculosis and control groups demonstrated almost similar patterns except for difference in stainability between groups. This indicates that glycoprotein, that had been already present in control bile, was markedly increased in hepatic bile in intrahepatic calculosis. SDS-PAGE also demonstrated a thick and deep-stained band near the starting point only in intrahepatic calculosis. 2) Chromatography obtained from gel filtration on Sepharose CL-6B revealed 2 large peaks, one in void volume (macromolecular) and the other in total volume (micromolecular) region. In chemical analysis, macromolecular fraction in intrahepatic calculosis was rich in galactosamine, fucose and sialic acid, and characterized by prominent serine and threonine, which indicated that it was composed mainly of mucin type sialoglycoprotein. The micromolecular fraction in both groups were rich in aspartic acid and mannose, which indicated that they were composed mainly of serum type glycoprotein.