GLP-1 mimetics and inhibitors of GLP-1 degradation are already licensed for the treatment of type 2 diabetes, exploiting the important role of GLP-1 in the stimulation and maintenance of insulin release from pancreatic β cells and in the control of appetite (Drucker and Nauck, 2006; Holst, 2007). Here, GCG is linked to type 2 diabetes mellitus.