Stimulated pancreatic exocrine secretion does not require pancreatic hyperemia in rats. Potential cholinergic role

Although blood flow and cholinergic tone influence gastric and salivary gland secretion, their role in pancreatic secretion is poorly defined. The purpose of the present study was: (1) to test the hypothesis that an increase in pancreatic blood flow accompanies stimulated pancreatic exocrine secretion, and (2) to examine the effects of cholinergic agents on basal and stimulated blood flow using hydrogen gas clearance. Stimulated pancreatic exocrine secretion (secretin 0.4, 0.8, 1.6 micrograms/kg/hr) resulted in a significant (P < 0.005) increase in secretory volume; however, pancreatic blood flow was not significantly changed, and a negative correlation between blood flow and secretion was observed. A pharmacologic dose of secretin (5.0 micrograms/kg/hr) resulted in a significant (P < 0.05) increase in pancreatic blood flow, which was inhibited by atropine (5.0 micrograms/kg/hr) infusion. Although 2-deoxyglucose caused a significant decrease (P < 0.03) in basal pancreatic blood flow, atropine had no effect on basal blood flow levels. These observations suggest that: (1) under physiologic conditions, secretin- or 2-deoxyglucose-stimulated pancreatic secretion does not require pancreatic hyperemia; (2) a pharmacologic dose of secretin does produce pancreatic hyperemia, perhaps through a local cholinergic mechanism; (3) peripheral cholinergic tone does not contribute significantly to basal pancreatic blood flow; and (4) basal pancreatic blood flow may be influenced by central mechanisms.