C-peptide constricts pancreatic islet arterioles in diabetic, but not normoglycaemic mice

BACKGROUND: Pancreatic islet blood flow is regulated separately from that of the exocrine pancreas, and a consistent finding during impaired glucose tolerance is an increased blood perfusion. The aim of the present study was to investigate whether C-peptide affects pancreatic islet arterioles in normal and diabetic mice. MATERIALS AND METHODS: Control and diabetic C57-Bl mice were studied after 2 weeks of alloxan-induced diabetes. Islet arterioles were dissected and microperfused with Dulbecco's modified Eagle medium (DMEM) solution. The effect of luminal application of mouse C-peptide was investigated. RESULTS: C-peptide reduced the diameter of islet arterioles from diabetic mice (-10+/-4%, P<0.05) compared to base-line values, whilst arterioles from normoglycaemic animals did not respond to C-peptide (P=0.2). CONCLUSION: These findings suggest a role for C-peptide in the regulation of islet blood flow, especially during conditions with impaired glucose tolerance.