Insulin infusion normalizes cardiovascular responses and plasma noradrenaline after oral glucose in type 1 (insulin-dependent) diabetes.

We examined whether the abnormal regulation of the cardiovascular system and plasma noradrenaline observed after oral glucose in insulin-dependent diabetic patients could be normalized by intravenous infusion of insulin. Eight patients with type 1 (insulin-dependent) diabetes were examined after an oral glucose load with and without simultaneous infusion of insulin. Insulin infusion increased plasma insulin from 0.07 to 0.31 nmol/l. In the control experiment (glucose only), mean heart rate and mean arterial systolic blood pressure remained unchanged and plasma noradrenaline (NA) decreased (p less than 0.05). After oral glucose plus intravenous insulin, mean heart rate increased by 11% and mean systolic blood pressure by 5% (p less than 0.05, p less than 0.01), whereas plasma NA did not change significantly. The present study indicates that physiologic increments in plasma insulin concentration are of importance in the regulation of the cardiovascular system and plasma NA following an oral glucose load.