Secretory protein 7B2 response to oral glucose loading and intravenous glucagon injection in patients with diabetes mellitus.

Serum 7B2 concentrations in control subjects and patients with diabetes mellitus were measured following a 75 g oral glucose load and following intravenous glucagon infusion. In response to oral glucose, serum 7B2 levels increased in the controls (n = 10) and in the diabetic patients (n = 7). The increment of the serum 7B2 level was smaller in the diabetic patients than the controls. During the 75 g oral glucose tolerance test (75g OGTT), serum 7B2 levels were significantly positively correlated with serum C-peptide levels. In contrast, following intravenous glucagon infusion, serum 7B2 levels increased only in diabetic patients treated with oral hypoglycemic agents (n = 20) and did not increase in controls (n = 5): the group having the highest insulin secretion activity in the present study, nor in diet or insulin-treated diabetic patients. No correlation between serum 7B2 levels and serum CPR levels was observed in the intravenous glucagon infusion study. These data suggest that an extra-pancreatic source which produces the observed serum 7B2 increase following oral glucose intake can not be excluded and that 7B2 may not be secreted concomitantly with insulin from the pancreatic beta cell in response to intravenous glucagon injection.