INS and type 2 diabetes mellitus: Given that insulin is a well known vasodilator whose actions are mediated via an endothelium-dependent pathway [10], [16], [17] and that insulin resistance has been associated with both endothelial dysfunction and reduced NO bioavailability [18], we sought to assess the role of insulin in L-arginine transport and endothelial function in man under normal physiological conditions and in type 2 diabetes.