Patients with an interrupted enterohepatic circulation of
bile acids and minimal or no
steatorrhea were studied to determine if their fat absorption was aided by compensatory mechanisms which delivered increased amounts of
lipid to the aqueous phase of post-prandial duodenal fluid. The data suggested that the molar stoichiometry of association of
fatty acid and
bile acid in an aggregated (
micelle) form was reduced in the patients (0.8) as compared to normals (1.4). Each patient had either normal sized or undetectable
micelles; one patient had a large
fatty acid-rich aggregated species. The
bile acid composition of the whole duodenal fluid was found to have an increased proportion of dihydroxy
bile acids which were conjugated with
glycine. There was a selective precipitation of dihydroxybile
acids from the aqueous phase, such that the patients had a normal proportion of these
bile acids in the aqueous phase. We were unable to identify a consistent compensatory mechanism whereby these patients could increase the concentration of
lipid in the aqueous phase which would have led to a better understanding of their minimal
steatorrhea. We believe that the reduced stoichiometry of aggregated
fatty acid to aggregated
bile acid is in part due to the altered
bile acid pool composition of these patients.