The intracellular renin-angiotensin system: a new paradigm.

More than a century after its discovery, the physiological implications of the renin-angiotensin system (RAS) continue to expand, with the identification of new components, functions and subsystems. These advancements have led to better management and understanding of a broad range of cardiovascular and metabolic disorders. The RAS has traditionally been viewed as a circulatory system, involved in the short-term regulation of volume and blood pressure homeostasis. Recently, local RASs have been described as regulators of chronic tissue effects. Most recently, studies have provided evidence of a complete, functional RAS within cells, described as an 'intracrine' or intracellular system. A more comprehensive understanding of the intracellular RAS provides for new strategies in system regulation and a more efficacious approach to the management of RAS-related diseases.