The cardiac renin-angiotensin system - Conceptual, or a regulator of cardiac function?

Angiotensin II, the effector peptide of the renin-angiotensin system, regul ates cellular growth in response to developmental, physiological, and patho logical processes. The identification of renin-angiotensin system component s and angiotensin II receptors in cardiac tissue suggests the existence of an autocrine/paracrine system that has effects independent of angiotensin I I derived from the circulatory system. To be functional, a local renin-angi otensin system should produce sufficient amounts of the autocrine and/or pa racrine factor to elicit biological responses, contain the final effector ( angiotensin II receptor), and respond to humoral, neural, and/or mechanical stimuli. In this review, we discuss evidence for a functional cardiac reni n-angiotensin system.