In vivo bile acid uptake from terminal ileum in cystic fibrosis.

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.