NOS3 and type 2 diabetes mellitus: However, while this reduction in vasodilator response to acetylcholine in T2DM could be due to impaired NO• generation as a consequence of decreased eNOS expression and activity, the authors also found that the vasodilator responses to the endothelium-independent NO• donor, sodium nitroprusside (SNP), were also attenuated in T2DM mammary arteries, indicating reduced vascular responsiveness to NO•, and hence the presence of NO• resistance.