Insulin - a vasoactive hormone

Abstract

Insulin is the single and the most important anti hyperglycemic hormone, whose metabolic actions are proven and are vital for the normal functioning of the body. Apart from being a metabolic hormone, insulin has been shown to be a vasoactive hormone also. The vasodilatation caused by insulin results in increased skeletal muscle blood flow, which has been coupled to the increase in muscle glucose uptake. The mechanism by which insulin causes this effect is not very clear but the role of nitric oxide release by vascular smooth muscle cells, adenosine, cyclic AMP, cyclic GMP and role of insulin on Na⁺-K⁺. ATPase has been proposed. The mechanism seems to be a complex one and further understanding is required. As various factors like insulin resistance and free fatty acid levels affect this vasodilatation, modulation of the vascular tone and skeletal muscle blood flow may be a novel therapeutic target to vercome the adverse effects of insulin resistance and reducing the complications associated with it.