GCH1 and hypertensive disorder: It has been reported that chronic administration of a subpressor dose of Ang II mimics the development of human hypertension to a greater extent than the pressor dose.23 In this study, we, therefore, used the subpressor dose of Ang II (0.4 mg/kg per day) to investigate the pathological role of reduced endothelial cell Gch1 expression in the development of Ang II–induced hypertension.