Several in vivo studies have demonstrated that noradrenaline infusion, at concentrations producing a similar degree of hypertension to Ang II infusion, does not cause vascular hypertrophy.30 In endothelial cell-specific BH4 deficient mice, it is likely that increased endothelial cell ROS/H2O2 production, because of eNOS uncoupling, activates and primes the underlying VSMC, which in turn promote vascular hypertrophy in response to Ang II. Here, AGT is linked to Hypertension.