Effect of extragastric vagotomy on pancreatic polypeptide in dogs

The direct vagal innervation of the pancreas in dogs was interrupted by extragastric vagotomy (EGV). The response of pancreatic polypeptide (PP) to a protein meal and to hypoglycemia was compared preoperatively, after EGV and after truncal vagotomy (TV). EGV had no detectable effect on PP secretion under basal or stimulated conditions. After TV, the PP response to a protein meal was reduced and totally abolished in response to insulin hypoglycemia when compared to preoperative results. This indicates that direct innervation of the pancreas is of little importance for the release of PP but that vagal innervation of the stomach is important provided that the vagal fibers to PP cells all pass through these extragastric vagal branches.