AGT and Hypertension: Hypertension is a major risk factor for coronary artery disease by impairing endothelium-dependent NO-mediated vasodilation (58) in the form of diminished bioavailability of NO, increased Ang II-dependent production of superoxide (59), and decreased endothelial levels of eNOS co-factor tetrahydrobiopterin (BH4) (60) or substrate l-arginine (61).