Effect of chronic changes in rate of enterohepatic cycling on bile acid kinetics and biliary lipid composition in the rhesus monkey.

Although several studies have demonstrated an inverse relationship between size of the bile salt pool and frequency of enterohepatic cycling, most such data have been obtained in conditions where control of cycling frequency was not possible. In this study, we diverted bile from the bile duct of Rhesus monkeys into a reservoir and returned it to the duodenum at varying rates, a model that mimicked differences in frequency of gallbladder emptying. As cycling frequency increased from 1 to 8 cycles/day, size of the bile salt pool decreased from 1756 microM to 369 microM. Changes in fractional turnover rate parallelled changes in cycling frequency. The relative composition of the biliary lipids remained the same throughout the range of cycling frequencies. These data show that direct manipulation of cycling frequency had the predicted effects on other parameters of the enterohepatic circulation but did not give rise to lithogenic bile.