GCG and diabetes mellitus: Lastly, we and others examined the contribution of central nervous system inputs to the alpha‐cells stemming from glutamatergic, GABAergic and noradrenergic neurotransmission as additional signals that may influence glucagon secretion, and while the release of these neurotransmitters may be affected by changes in local glucose and insulin concentrations in diabetes, a complete picture of their role is still outstanding.10, 35, 36, 37, 38