Relative lipid compositions of bile specimens from CCK-1R^–/– and WT mice. Relative lipid compositions (mol per 100 mol) are plotted on partial condensed phase diagrams according to the approximate total lipid concentrations of the bile samples (A, 10.0 g/dl for gallbladder bile; B, 2.0 g/dl for hepatic bile; see Table 1). The one-phase micellar zone (at bottom) is enclosed by a solid curved line, and two solid and two dashed lines divide the phase diagram into regions a–e with different crystallization sequences (see ref. 24). (A) Lipid compositions of pooled gallbladder bile specimens (n = 20 per group) from the CCK-1R^–/– (circle) and WT mice (square) fed the lithogenic diet for 12 weeks are located in a central three-phase area where, at equilibrium, bile samples are composed of cholesterol-saturated mixed micelles, solid cholesterol crystals, and liquid crystals, as observed by microscopy. (B) Analogous regions of the condensed phase diagram exhibit the same physical states at equilibrium as those in the phase diagram shown in A; however, with decreases in total lipid concentration all crystallization pathways are shifted to the left and the micellar zone becomes smaller. These alterations generate a new condensed phase diagram with an enlarged region e. Lipid compositions of individual hepatic bile specimens (n = 6 per group) from both WT (squares) and CCK-1R^–/– mice (circles) locate in region e, where, at equilibrium, the bile samples are composed of liquid crystals and saturated micelles, but no solid cholesterol monohydrate crystals are present.