Obese subjects of the normative aging study were shown to be sensitive to the effects of insulin on sympathetic activity despite resistance to the effects of insulin on glucose uptake and displayed an increased 24-h urinary norepinephrine excretion [13], the amounts of norepinephrine excreted being related to the degree of obesity [14]. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.