EFFECTS OF INTRAVENOUS-INFUSION OF SECRETIN ON BILE SECRETION IN HUMANS

Objective: To investigate the effects of secretin on canalicular and d uctular bile secretion in humans. Methods: The effects of intravenousl y administered secretin on bile secretion were studied in seven patien ts with complete biliary fistulas. The clearance of [C-14]-mannitol wa s used to determine the canalicular bile flow. Results: During secreti n infusion, bile volume increased four-fold. Although secretin did not increase bicarbonate concentration, the output increased four-fold du ring secretin infusion. The outputs of bile acids and phospholipids we re not significantly affected, although their concentrations decreased by 65% following secretin infusion. Cholesterol output was increased by 30-35% after secretin stimulation. The canalicular bile flow, as me asured by [C-14]mannitol, increased by 75%. Assuming that mannitol cle arance is a reliable marker of canalicular bile secretion, and given t hat the total increase in bile secretion was about four-fold, the incr ease at the ductular level was calculated to be about seven-fold. Conc lusion: The present data suggest that secretin exerts an effect at bot h the ductular and the canalicular level.