Colloid chemical aspects of pigment lithiasis in man: solubilization of calcium bilirubinate by bile salts (a preliminary report).

Calcium bilirubinate, an important constituent of pigment gallstones, can be solubilized in aqueous systems (including bile) to a considerable extent, depending on colloid mechanisms, strongly influenced by the actual ionic strength. Simple bile salt micelles protect colloid calcium bilirubinate against coagulation more effectively than do mixed bile salt-lecithin micelles, in particular when the latter are cholesterol saturated. The dissolved pigment does not enter the bile salt micelle. Pigment stone formation is believed to be due not merely to calcium bilirubinate overproduction, but also to pathological conditions leading to a coagulation of the colloid pigment in bile.