GCG and diabetes mellitus: Furthermore, the rationale behind the strategy to use pancreatic alpha cells from the same organ (pancreas) for trans-differentiation is the fact that alpha-to-beta cell trans-differentiation can lead to restoration of beta cell mass, but it also simultaneously reduces alpha cell mass and thus restores the balance between pancreatic hormones (insulin and glucagon), which is perturbed in diabetes (bihormonal hypothesis of diabetes) (46).