GCG and type 2 diabetes mellitus: Taken together, this evidence suggests the following: (a) the CB directly senses blood insulin and acts in the balance of insulin/glucagon secretion; (b) insulin stimulates the CB and promotes physiological responses via sympatho-excitation; (c) the chronic overactivation of the CB increases tonic SNS activity, and elicits insulin resistance and dysmetabolism; and (d) insulin-mediated overactivation of the CB appears to be an early and functional predictor of type 2 diabetes.