Gastric inhibitory polypeptide secretion after gastrectomy in patients with diabetes mellitus.

Gastric inhibitory polypeptide (GIP) secretion after distal gastrectomy was compared between patients with diabetes mellitus (DM-group) and patients with normal glucose tolerance (N-group). GIP secretion in the DM-group was significantly greater in the early postcibal response period, but less in the late postcibal response period after gastrectomy, the total secretion of GIP being less after gastrectomy than before in this group. In the N-group, both the early and total postcibal responses of GIP were greater after gastrectomy than before. Moreover, the early and total postcibal secretions of GIP after gastrectomy were less in the DM-group than in the N-group. These findings suggest that GIP secretion in diabetics becomes insufficient after gastrectomy.