Microvascular endothelium-dependent and -independent vasodilatation are investigated in patients with T2DM (n =12) and healthy age-matched control subjects (n =12) with laser-Doppler flowmetry during iontophoretic application of acetylcholine and sodium nitroprusside, respectively, before and after intra-arterial administration of the arginase inhibitor N-hydroxy-nor-L-arginine (0.1 mg/min) for 120 min.