HORMONAL RESPONSES TO INSULIN INFUSION IN DIABETES-MELLITUS

Twenty diabetic patients and fourteen normal volunteers received infusion of 2.4 U neutral porcine insulin/h until either the blood glucose level was stable, or until hypoglycaemia occurred. As previously reported [1] in the normal group the blood glucose stabilised at 2.8±0.1 mmol/l without any hypoglycaemic symptoms. There was an increase in blood levels of glucagon, cortisol and growth hormone as the blood glucose level fell, the mean peak increments being 167±33 pg/ml, 400±71 nmol/l and 29±7 mU/l, respectively. In ten of the diabetic subjects (Group A) the blood glucose level stabilised at 3.6±0.2 mmol/l during the insulin infusion, with peak increments in plasma glucagon (110±24pg/ml), cortisol (411±71 nmol/l) and growth hormone (22±6 mU/l), not significantly different from those in the normal subjects. These rises in hormone levels occurred during the last hour of infusion after normoglycaemia was reached and maintained. The ten remaining diabetics (Group B) developed symptoms of hypoglycaemia during the infusion. The peak increments in plasma glucagon (19±7 pg/ml), cortisol (183±36 nmol/l) and growth hormone (6±2 mU/l) in this latter group were significantly less than those in the other diabetic group or the normals. The absence of counter-regulatory hormonal responses in the Group B diabetics was related to the development of hypoglycaemia and may be the result of a dysfunction of hypothalamic gluco-regulatory centres. © 1979 Springer-Verlag.