Relationship between the Biliary Excretion of Bile Acids and the Excretion of Water, Lecithin, and Cholesterol in Man

The relationship between the biliary excretion of bile acids and the excretion of water, lecithin, and cholesterol was studied within a wide range of bile acid excretion rates in 5 patients operated on for nonobstructive gallstone disease. The bile acid excretion rate was varied by interruption of the enterohepatic circulation (EHC) and by duodenal refeeding of bile acids during interrupted EHC. A linear relationship between the bile acid excretion rate and the water excretion rate was found. In 2 of the patients the cholesterol excretion rate seemed to be independent of the bile acid excretion rate and in two of the remaining cases a linear relationship between the excretion rates of these lipids was broken at bile acid ex cretion rates below 5 μmoles/min. The biliary excretion rate of lecithin was related to the bile acid excretion rate in a nonlinear way. This relationship suggests that the determining role of bile acids in the EHC for the biliary excretion of lecithin cannot be related primarily to the excretory mechanism in the hepatocytes. However, the findings are compatible with the hypothesis that the bile acids in the EHC affect primarily the synthesis of lecithin in the biliary excretion pool.