Abstract

The cause(s) of excessive fecal bile acid loss in cystic fibrosis (CF) has not yet been fully determined, but in vitro studies have suggested that a primary mucosal defect in ileal bile acid uptake may be of importance. To examine this mechanism in vivo, the terminal ileal uptakes of taurocholate and glycocholate were determined using a marker-perfusion technique in three CF infants and four controls. Normal and CF ileal conditions were stimulated by varying the taurocholate:glycocholate concentration ratio (normal 1:1, CF 1:4) and pH (normal 7.8, CF 6.0) of the perfusate. The mean bile acid uptake under normal perfusate conditions was not significantly different in CF subjects (taurocholate 0.124 mumol/min/cm ileum +/- SD 0.127, glycocholate 0.117 mumol/min/cm ileum +/- 0.114), and controls (0.142 +/- 0.164 and 0.115 +/- 0.120 respectively). Similarly, under CF conditions, bile acid uptake values in CF subjects and controls were similar. The results are not consistent with deranged ileal bile acid reabsorption being a major cause of fecal bile acid loss in CF.