Vasoactive intestinal peptide (VIP) cells in the pancrease and gastro-intestinal mucosa. An immunohistochemical and ultrastructural study.

Using antibodies against pure porcine VIP in immunoperoxidase and immunofluorescence tests, VIP-immunoreactive cells have been detected in the pancreas-especially in the islets-and gastrointestinal mucosa of the dog, guinea-pig and man. VIP immunoreactive cells were widely distributed in these tissues, never being numerous at any site. Some parallelism has been noted between such cells and ultrastructurally identified D1 cells fo the pancreas and gastrointestinal mucosa. The presence of VIP cells in normal pancreas may help explain the occurrence of pancreatic endocrine tumors producing VIP.