Two GLP-1 mimetic drugs are now widely used to treat type-2 diabetes, exendin-4/exenatide and liraglutide, because of their optimal glucose lowering capacity with low risk of hypoglycemia (Chia and Egan, 2008; Buse et al., 2009; Nauck et al., 2009). Here, GCG is linked to type 2 diabetes mellitus.