Pancreatic polypeptide in insulinomas, gastrinomas, vipomas, and glucagonomas

In 33 patients studied with endocrine neoplasms of the pancreas more than half the tumors contained pancreatic polypeptide (P.P.) producing cells, and a high radioimmunoassayable concentration of P.P. was found in the tumor extracts. Plasma was available from 28 patients, and very high circulating P.P. concentrations were found in 18. The presence of P.P. in hepatic and lymphnode metastases indicates that its production by the primary neoplasm cannot be ascribed to incidental adherence of normal P.P. cells. Measurements of plasma P.P. levels should be a new aid to diagnosis of pancreatic tumors.