GIP and type 2 diabetes mellitus: Currently, DPP4 is a drug target for the treatment of diabetes type II, because of its involvement in the hydrolysis of the incretins GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) which induce glucose-dependent insulin secretion and are related to β-cells protection and proliferation [5,6].