Evidence for pyloropancreatic reflux for pancreatic exocrine secretion

In seven dogs provided with innervated pouch of the pyloric antrum, gastric fistula, and chronic pancreatic fistula, the effect of graded antral distenion on pancreatic exocrine secretion was studied. The effect of antral distension was tested both when gastrin release was promoted (alkaline distention) and when gastrin release was blocked (acid distension). These studies were performed both before and after transthoracic truncal vagotomy. Graded alkaline antral distension caused graded rise in protein-rich pancreatic secretion and graded increase in the concentration of serum immunoreactive gastrin. A similar pancreatic response was also seen with graded acid distention although this time no rise in serum gastrin concentration occurred. Pancreatic response to antral distension with either alkali or acid is completely inhibited by pretreatment of the animals with systemic atropine. Truncal vagotomy reduced pancreatic response to alkaline antral distension by 90% but completely abolished pancreatic response to distension of the antrum with acid. These studies provide evidence for a pyloropancreatic reflex mechanism for pancreatic secretion that is cholinergic and requires intact long vagal pathways.