In T2DM patients during hyperglycemic clamp studies, infusion of GLP-1, but not GIP, stimulates insulin secretion, thus showing that the insulinotropic effect of GLP-1 is reasonably well-preserved in T2DM, despite possibly lower levels, when compared to nondiabetic individuals [120, 121]. The gene discussed is GCG; the disease is type 2 diabetes mellitus.