Response of islet cell tumors to enterohormones

The insulin response to oral glucose, tolbutamide, arginine, pancreozymin and cerulein was studied in a group of subjects with insuloma and a group of normal control subjects. The same parameters were studied in a small number of cases after administration of secretin and gastrin. The glucagon response (IRG) to arginine, pancreozymin and cerulein was also studied. In subjects with insulomas plasma IRI values after oral glucose, tolbutamide and pancreozymin, starting from elevated basal levels, reached high absolute levels though the increase above basal levels did not differ significantly from normal. After cerulein plasma IRI values increased in some insuloma patients but not in normal subjects. After arginine the plasma IRI increase above basal levels was significantly lower than normal in patients with insulomas. The glucagon response to arginine was normal in the patients with insulomas; these patients showed a clearcut glucagon response to cerulein and a very irregular response after pancreozymin.