Hormonal control of pancreatic secretion by intrajejunal HCl: studies in dogs with an autotransplanted entire jejunoileum.

To elucidate the role of hormones in the control of pancreatic secretion, we developed, in seven dogs, a model of total extrinsic denervation of the jejunoileum by autotransplanting this segment of bowel. A Thomas-like cannula was placed into the stomach, the duodenum (to collect pure pancreatic juice), and the proximal part of the jejunum. Thus, intestinal stimulants could only stimulate the pancreas via release of humoral (= hormonal) mediators. Seven control dogs received only the three fistulas. After recovery, dose-response curves of pancreatic bicarbonate and protein response to perfusion of the extrinsically denervated or innervated jejunoileum with HCl (1.5 to 48 mmol h-1) were performed with and without atropine (14 nmol kg-1 h-1 i.v.). Plasma levels of secretin were determined by radioimmunoassay. The maximal bicarbonate output occurred in response to 24 mmol h-1 of HCl and was significantly (p less than 0.05) higher in intact as compared to denervated animals. Atropine only significantly depressed the bicarbonate response to HCl in dogs with a denervated jejunoileum. HCl caused a dose-dependent increase in plasma levels of secretin, which was not altered by denervation and/or atropine. Irrespective of the innervation of the small bowel, pancreatic protein output was only significantly stimulated above basal when high loads (12-48 mmol h-1) of HCl were given. Atropine significantly reduced these responses.(ABSTRACT TRUNCATED AT 250 WORDS)