Pancreatic polypeptide in patients with type 1 diabetes and exocrine failure or chronic pancreatitis. The DIAPP study

.- Exocrine dysfunction can occur in type 1 diabetes (T1D). When exocrine function is impaired, it is unclear whether alterations also involve other endocrine cell types beyond beta cells. Pancreatic polypeptide (PP) is, besides insulin, the sole hormone that is specific to islets of Langerhans. The aim of the DIAPP study was to evaluate if PP secretion is also altered when T1D is complicated by exocrine failure.

. - Seven patients with T1D and normal pancreatic function (T1DN), 9 patients with T1D and exocrine failure (T1DEF) were compared to 13 patients with type 3c diabetes; i. e. with chronic pancreatitis (CP). All of them had a mixed meal test (MMT), C-peptide and PP being determined before and at 60, 90 and 120 minutes.

. - The area under the curve of C-peptide during MMT (AUC_Cpep) was significantly greater in the CP group than in both T1D groups (P < 0.0001 vs. the T1DEF group and P < 0.001 vs. the T1D group) while the area under the curve of PP (AUC_PP) was significantly smaller in the CP group than in both T1D groups (P < 0.01 vs. both groups). The AUC_PP / AUC_Cpep ratio was higher in the CP group than in both T1D groups (P < 0.0001 vs. both groups).

. - PP secretion was altered specifically in patients with CP, not in T1D, even when associated with pancreatic exocrine failure.