A standardized meal stimulation test of the endocrine pancreas for early detection of pancreatic endocrine tumors in multiple endocrine neoplasia type 1 syndrome: five years experience.

Forty-nine members of 6 families with multiple endocrine neoplasia type 1 (MEN 1) were investigated with a standardized meal stimulation test to detect the presence of pancreatic endocrine tumors. Fifteen age-matched subjects and 4 patients with primary hyperparathyroidism also were studied. Serum pancreatic polypeptide (PP), gastrin, and insulin as well as plasma glucagon and somatostatin concentrations were determined before and during the test meal. Patients with demonstrable pancreatic endocrine tumors had significantly increased mean basal and peak serum PP (P less than 0.001) and gastrin (P less than 0.001) responses to the meal compared with healthy family members and normal subjects. Seven of 12 MEN 1 patients with parathyroid and pituitary disease but no demonstrable pancreatic endocrine tumors had exaggerated PP and/or gastrin responses to the meal; 4 of them developed pancreatic endocrine tumors, detected by abdominal computerized tomography, 0.5-4 yr later. None of the healthy members of the MEN 1 families or the patients with primary hyperparathyroidism had responses different from those of the normal subjects. Our experience with the meal stimulation test indicates that an elevated basal or exaggerated serum PP and/or gastrin response is an earlier sign of pancreatic involvement in the MEN 1 trait than is abdominal computerized tomography.