Type 2 diabetes is a complex metabolic disease and decreased beta-cell mass, beta-cell dysfunction, and increased insulin resistance have been reported to be important in its pathogenesis; however abnormal pulsatility of basal insulin secretion, loss of first-phase of insulin release, and increased glucagon secretion also contribute to the development of type 2 diabetes (3, 4). Here, GCG is linked to type 2 diabetes mellitus.