The dominating macromolecular complex of human gallbladder bile

Abstract

The solutes of human gall bladder bile appear to exist mainly in the form of a complex macromolecule, formed around a nucleus of lipoprotein. The existence of this macromolecule was demonstrated by paper electrophoresis1, free electrophoresis and ultracentrifuge experiments. The molecular weight of the compound was found to be of the magnitude of 26,000. Evidence was obtained that the complex has no completely constant composition. The main molecular constitution per molecule of the complex was calculated as: 0.57 mol. bilirubin, 3.4 mol. cholesterol, 39.8 mol. desoxycholic acid and 7.3 mol. lecithins, probably grouped around one or more molecules of a polypeptide with a molecular weight below 10, 000. As this complex is the main macromolecular constituent of gall bladder bile and contains all the bilirubin present, and about 80% of the cholesterol, it must be involved in stabilising the gall bladder bile and thus be related to gallstone formation. The concentration of the complex was found to be lower, the more inflammatory signs were present in the gall bladder. The properties of the complex, such as stability, resistance to extraction procedures, precipitation and staining properties, were studied. Finally, the occurrence of the bili-lipoprotein was studied in 360 bile samples, 64 from gall bladder bile, all obtained by puncture of the gall bladder during surgery, and 296 samples of fistula bile and samples obtained by puncture of the hepatic duct during surgery. The lipoprotein complex, always abundantly present in gall bladder bile if no inflammation of the gall bladder exists, was absent in 2/3 of the fistula bile samples. In fistula bile it is never found in concentrations as great as in gall bladder bile. Artificial concentration of fistula bile that contains an appreciable amount of the complex seldom gave a product that was equal to or closely resembling gall bladder bile. These and other facts suggest production of lipoprotein within the gall bladder, and in minor quantities under certain conditions by the walls of the bile passages.