GCK and type 2 diabetes mellitus: We evaluated GCK expression by measuring the average immunoreactivity of GCK in insulin+ or glucagon+ cells from pancreatic sections of 11 nondiabetic subjects (ND), 10 subjects with impaired fasting glucose (IFG), 9 with well‐controlled T2D (wT2D), and 5 individuals with poorly controlled T2D (uT2D).