INTRACEREBROVENTRICULAR SECRETIN ENHANCES PANCREATIC VOLUME AND BICARBONATE RESPONSE IN RATS

Background. Although secretin has been found within the brain, its cen tral role in pancreatic exocrine function has not been previously addr essed. The hypothesis that intracerebroventricular secretin enhances p ancreatic volume and bicarbonate output at doses that have no effect w hen given intravenously was tested. Methods. Sprague-Dawley rats had a cannula stereotactically placed into the left lateral cerebral ventri cle 24 hours before study. At laparotomy the bile and pancreatic ducts were separately cannulated and excluded for tared collections and bic arbonate assay. Results. Increasing doses of intracerebroventricular s ecretin (0.005, 0.05, and 0.5 mu g/1.0 mu l) induced a significant dos e-related increase in bicarbonate output (2.95, 3.35 and 4.02 mu Eq/30 min, respectively) above basal (2.62 mu Eq/30 min) compared with cont rol or intracerebroventricular saline treated animals. Pancreatic volu me increased to 59.7 mu l at the lowest intracerebroventricular dose a nd increased (p < 0.025) to 65.8 mu l at the 0.05 intracerebroventricu lar secretin dose when compared with basal 15.4 mu l). To show that th is was not a systemic effect of secretin, intravenous infusion of secr etin at 0.005 and 0.05 mu g/kg/hr failed to stimulate either volume or bicarbonate output compared with that observed with intracerebroventr icular secretin over the same dose range. Conclusions. These observati ons indicate that intracerebroventricular secretin stimulates pancreat ic volume and bicarbonate output and suggest that central secretin may play a role in the regulation of exocrine pancreatic secretion.