Effects of pancreatic polypeptide and vasoactive intestinal polypeptide on rat ileal and colonic water and electrolyte transport in vivo.

Two gastrointestinal peptides, vasoactive intestinal polypeptide (VIP) and pancreatic polypeptide, suspected of being associated with symptoms of WDHA syndrome (pancreatic cholera) were tested on the rat small and large intestine for their effects on water and electrolyte transport. Intravenous infusion of VIP (14.3 microgram/kg/hr) inhibited net absorption of water and electrolytes in the ileum and reversed net absorption to net secretion in the colon. In contrast, bovine pancreatic polypeptide (52 microgram/kg/hr) did not inhibit absorption or stimulate secretion. These data indicate VIP causes colonic secretion in vivo, an effect previously shown only in vitro, and that bovine pancreatic polypeptide (at this dose) is not a secretagogue in the small or large intestine of the rat. Thus, while consistent with VIP being a contributory agent to the secretion of pancreatic cholera, the data do not support the notion that pancreatic polypeptide might be a causative agent in this syndrome.