HEPATIC BILE VERSUS GALLBLADDER BILE - A COMPARISON OF PROTEIN AND LIPID-CONCENTRATION AND COMPOSITION IN CHOLESTEROL GALLSTONE PATIENTS

Many studies have demonstrated that gallbladder bile (but not hepatic bile) of animals or patients with cholesterol gallstones contains high er protein concentrations than does gallbladder bile of control patien ts without stones or with pigment stones. The underlying defect has no t been elucidated. To establish whether there is net production or net absorption/degradation of protein by gallbladder epithelium for diffe rent classes of protein, paired samples of hepatic and gallbladder bil e were obtained from fourteen patients with cholesterol gallstones dur ing elective cholecystectomy. In these paired samples, lipid and prote in composition were determined. To obtain the concentration ratio (CR) of protein and lipid, its concentration in the gallbladder was divide d by the concentration determined in the paired hepatic bile sample. T he CR of bile salts was used as a parameter for water absorption in th e gallbladder. Of the biliary proteins that were determined only mucin , albumin, immunoglobulin (Ig) G, and aminopeptidase N appeared to inc rease in the gallbladder from another cause than water absorption. A s trong correlation was found between mucin, albumin, and IgG. Haptoglob in, alpha(l)-acid glycoprotein, IgM, and IgA appeared to be absorbed b y gallbladder epithelium in the majority of patients. In cholesterol g allstone patients, total protein concentration in gallbladder bile of cholesterol gallstone patients is increased when compared with hepatic bile. The increase in protein concentration cannot be explained for a ll bile samples solely by water absorption, In this study we show that the defect is largely caused by a selective increase in albumin, muci n, and IgG. All other proteins which were investigated are taken up by the gallbladder.