In T2D, virtually every organ system contributes to dysglycemia, as encapsulated by the “ominous octet” of mechanisms—β-cell failure, α-cell excess, hepatic- and skeletal-muscle insulin resistance, adipose dysfunction, central appetite dysregulation, heightened renal glucose reabsorption, and an impaired incretin effect [4]. Here, GCG is linked to type 2 diabetes mellitus.