Biliary lipids, bile acids and gallstone formation in hypovitaminotic C guinea-pigs.

1. Hypovitaminotic C guinea-pigs fed on a high-cholesterol diet for 5 weeks developed gallstones (810 mg cholesterol/g) whereas no concretements were observed in vitamin C-replete animals. 2. Scanning electron microscope studies of the three types of gallstone observed in the gallbladders of vitamin C-deficient animals showed them to be composed of randomly-arranged needle-shaped or laminated crystal of cholesterol. 3. The hepatic bile of gallstone-forming animals had a higher cholesterol concentration and lower bile acid content, the latter being principally due to a reduction in the chenodeoxycholic fraction, than the bile of vitamin C-replete animals. 4. No significant difference was observed between the volume of bile secreted by hypovitaminotic C and vitamin C-replete animals, but due to the qualitative changes in bile composition, gallstone formation was associated with an increased biliary secretion of cholesterol and a reduced secretion of bile acids.