GW274150 shows less potency for both humans or rats endothelial NOS (eNOS) and neuronal NOS (nNOS).gW274150 is a selective and NADPH-dependent inhibitor of human inducible nitric oxide synthase (iNOS) (IC50=2.19 μM; Kd=40 nM) and rat iNOS (ED50=1.15 μM).