The renin–angiotensin system (RAS), critically involved in the control of blood pressure and
volume homeostasis, is a dual system comprising a circulating component and a local tissue
component. The rate limiting enzyme is renin, which in the circulating RAS derives from the
kidney to generate Ang II, which in turn regulates cardiovascular function by binding to AT1
and AT2 receptors on cardiac, renal and vascular cells. The tissue RAS can operate
independently of the circulating RAS and may be activated even when the circulating RAS is …