[Effect of free fatty acid on cholesterol nucleation in model bile].

We studied the effect of free fatty acids on cholesterol nucleation in model bile with a sensitive cholesterol crystal growth assay. Palmitic acid, oleic acid, linoleic acid and arachidonic acid were added to model biles in increasing concentrations from 0.5 to 20 umol/ml. The nucleation time of model bile with free fatty acids decreased to 30%-50% of control bile. The final crystal concentration increased with higher concentrations of palmitic acid. However, we found a decrease in the final crystal concentration with the unsaturated fatty acid-soleic acid, linoleic acid and arachidonic acid. The increase in the maximum crystal growth rate was marked in the model biles as linoleic acid was added. These findings show the effect of non-protein fraction in biles on gallstone formation and support the view that free fatty acids are pro-nucleating factors.