INS and obesity due to melanocortin 4 receptor deficiency: Furthermore, insulin resistance, which characterizes human obesity and involves also the vascular effects of the hormone [115, 123, 165, 166], can determine per se hemodynamic consequences by impairing the balance between the vasodilating insulin actions exterted via the NO/cGMP/PKG pathway and the vasoconstricting-ones mainly exerted via ET-1 in favour of the last-ones, as extensively reviewed [22, 78, 84, 115, 123, 167].