Sitagliptin (MK-0431) is an orally active and highly selective DPP4 inhibitor with an IC50 value of 19 nM. Sitagliptin blocks the degradation of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) by competing inhibition mechanism (K = 1 nM), thereby increasing the level of active incretin. Sitagliptin can also directly stimulate the secretion of GLP-1 by intestinal L cells by activating the cAMP/PKA and ERK1/2 pathways, and this effect is independent of DPP-4. Sitagliptin shows protective effects on pancreatic islet grafts in 1-type diabetes models. Sitagliptin can be used for the study of 1-type and 2-type diabetes[1][2][3][4][5].
