Effects of continuous and intermittent feeding on biliary lipid outputs in man: application for measurements of intestinal absorption of cholesterol and bile acids.

Hepatic outputs of biliary lipids can be measured by intestinal perfusion techniques, either during constant infusion of liquid formula into the duodenum or through-out a 24-hour period during which time three meals are given along with an overnight fast. The purpose of this study was to compare these two methods for estimating secretion of biliary lipids. In 21 subjects, mean hourly outputs measured during continuous feeding were highly comparable to those during intermittent feeding, showing that the constant infusion technique gave valid estimations of overall daily secretion rates of biliary lipids. On the other hand, the intermittent mode of feeding showed phasic changes of outputs and composition of biliary lipids in response to feeding and fasting apart from total outputs over 24 hours. However, it takes longer to complete and requires the use of a meal marker. By combining the intestinal perfusion technique with measurements of fecal excretion of neutral steroids and bile acids, this method may be used to estimate absorption of cholesterol and bile acids from the intestine. Thus, these measurements allow quantification of a number of parameters of the enterohepatic circulation.