Effects of intra-arterial infusion of insulin on control of forearm vascular resistance in normotensive and hypertensive subjects.

In this article, I will review the recent progress in the relationship between hyperinsulinemia and control of vascular resistance. I particularly focus on effects of intra-arterial infusion of insulin on control of resting forearm vascular resistance and on vascular reactivity to vasoconstrictor agents in normotensive and hypertensive subjects. In conclusion, the physiological levels of local hyperinsulinemia may decrease resting forearm vascular resistance in some normotensive subjects but not in all. Insulin-induced vasodilation may be due to the production of prostacyclin but not due to nitric oxide. Hyperinsulinemia attenuates vasoconstriction induced by phenylephrine and angiotensin II in normotensive subjects. Although acute intra-venous infusion of insulin activates the sympathetic nerve system, it may not elevate blood pressure in normotensive subjects possibly due to above mentioned anti-vasoconstrictor effects of insulin. In contrast, insulin-induced anti-vasoconstrictor mechanisms may be lost in hypertensive subjects, which may result in hypertension.