DPP4 and type 2 diabetes mellitus: Since GLP-1 is the substrate of DPP4 enzyme that can cleave circulating GLP-1, inhibition of DPP4 enzyme activity by sitagliptin, a drug for the treatment of type II diabetes mellitus and a DPP-IV inhibitor, has been reported to enhance the circulating GLP-1 level [14,20-23] which has also been found to be increased in DPP4-deficient animals and in acute kidney IR injury [14,22].