DPP4 and type 2 diabetes mellitus: The effect of GLP-1 is conserved in patients with type 2diabetes, whereas the effect of GIP is severely impaired [6,5].Continuous intravenous infusion of GLP-1 can normalize blood glucose concentrationsin diabetic patients [7], butintravenous GLP-1 is quickly degraded, and not feasible for routine clinical use.GLP-1 is rapidly degraded by the enzyme DPP-4 and it is no longer available inactive form [8,9].