GCG and type 2 diabetes mellitus: DPP-4 inhibitors that prevent DPP-4 from degrading GLP-1, e.g., Sitagliptin, and GLP-1 receptor agonists that affect GLP-1 to last longer, e.g., Liraglutide, are of particular interest for their glucose-lowering effects, which are useful to the treatment of T2D [49].