[The study on factors affecting cholesterol solubility in bile: relation to biliary proteins including apolipoprotein A-1].

We studied the preferential distribution patterns of cholesterol and proteins to biliary lipid particles isolated from human gallbladder bile by gel permeation chromatography. In addition nucleation times of those bile samples were determined to estimate the metastability of bile cholesterol. Cholesterol dominantly incorporated into a non-micellar fraction in bile from cholesterol gallstone patients with and without preoperative treatment with ursodeoxycholic acid, whereas nucleation time was significantly longer in cholesterol gallstone patients with a preoperative treatment with ursodeoxycholic acid than that of those without any preoperative treatment (p less than 0.01). Furthermore the induced incorporation of apolipoprotein A-1 into a non-micellar fraction was found in bile from cholesterol gallstone patients with ursodeoxycholic acid. These results suggest that stabilizing effects of apolipoprotein A-1 on a non-micellar fraction has been induced by ursodeoxycholic acid treatment resulting in the retardation of cholesterol nucleation in bile.