The incretin-based pharmacotherapies have emerged as potential anti-diabetic strategies which include DPP-IV inhibitors, GLP-1 analogs/mimetics,[4, 7] and GLP-1 secretagogues.[14–16] The basis of the incretin approach was originated with the proposal of using DPP-IV inhibitors to treat T2DM.[17] DPP-IV inhibition in vivo should elevate both plasma active GLP-1 and insulin after a meal leading to glucose lowering.[17, 18] As mentioned earlier, though there has been an in-depth kinetic analysis of various DPP-IV inhibitors,[1, 10] there is not much information available for sitagliptin. The gene discussed is GCG; the disease is type 2 diabetes mellitus.