[The renin-angiotensin system: systemic and local function].

The renin-angiotensin system (RAS) has long been known as a hormonal system, which is important for the maintenance of volume homeostasis, and which contributes under certain circumstances to the pathogenesis of hypertension and cardiac failure. More recent findings have demonstrated that the individual components of this system can also be synthesized locally in tissue, e.g. in the brain, the vascular wall, the kidney, the adrenals, and the heart. Although the role of locally generated angiotensin within cardiovascular- and body volume regulation needs to be further investigated, it has already become clear that the mechanism of action of drugs interfering with the RAS is not confined to the circulating RAS, but also includes an interaction with local renin-angiotensin systems. These agents, particularly the converting enzyme inhibitors, have proved to be indispensible tools for elucidating the function of local renin-angiotensin systems, in addition to being therapeutically useful in the treatment of cardiovascular diseases.