Serotonin in the portal vein after acidification

To test whether serotonin release from the argentaffin cells of the intestinal tract can elicit peptic ulcer, rats were given intraduodenal infusions of N/10 and N/20 hydrochloric acid. Serotonin measured in the portal venous blood of rats which had had an intraduodenal infusion of N/20 HCl for five minutes was significantly higher than in the portal (P less than 0.05) or systemic (P less than 0.01) blood of control animals. After longer intervals serotonin release tapered off and measurements obtained 30 minutes after an infusion of N/10 HCl did not differ significantly from those in the controls.