Cardiovascular actions of insulin in humans. Implications for insulin sensitivity and vascular tone.

Insulin has a plethora of actions, most of which are initiated after interaction with its specific cell surface receptor on classical target tissues. Prominent among these actions is its ability to increase cellular permeability to glucose in muscle and fat. Heretofore, the cardiovascular actions of insulin in humans have received little attention. The effects of insulin on the cardiovascular system and, in particular, on skeletal muscle vasculature are physiological, specific, co-ordinated and appear to play an integral part in its overall action to promote the disposal of glucose and probably other substrates. The vascular actions of insulin should be added to the long list of actions initiated by this hormone, and are important to consider in the study of in vivo metabolism in health and disease.