GCG and type 2 diabetes mellitus: The approach to elevate endogenous GLP-1 levels by inhibition of the predominant GLP-1 degrading enzyme, dipeptidyl peptidase-IV (DPP-IV), has been proven useful for T2DM treatment [21], but does not seem to fully capture the anti-diabetic potential of GLP-1R agonism [22] in terms of promoting weight loss [23].