The effect of secretin on bile flow and bile acid and bilirubin excretion following relief of prolonged bile duct obstruction in the rat.

Bile flow was re-established in rats whose bile ducts had been obstructed for 5, 10, 15 and 28 days (Groups I, II, III and IV, n = 5). The effect of i.v. secretin on bile flow in control rats, whose bile ducts had been cannulated, was minimal, but in cholestatic rats there was an immediate response which was related to the duration of the obstruction and the degree of bile duct proliferation. In 40 min the mean excess bile flow production amounted to 76, 258, 320 and 432 microliters/100 g body wt. in Groups I, II, III and IV, respectively. Choleresis was prolonged in the Group IV rats that had developed cirrhosis. Synthetic secretin had a minimal effect on bile acid and bilirubin excretion. It is postulated that the proliferating bile ductules are the site of secretin choleresis, although the possibility that reduced inactivation of the hormone plays a role cannot be excluded.