Angiotensin II: biosynthesis, molecular recognition, and signal transduction.

1. Angiotensin II is a well-known vasopressive octapeptide that is the principal end-product of the renin-angiotensin system. In addition to its tonic effect on vascular smooth muscle cells, it also stimulates aldosterone secretion from the adrenals and promotes sodium reabsorption through renal tubular cells. 2. These physiological functions have been appreciated for some time, but as details of the molecular and cell biology of the angiotensin response mechanism become understood, it is increasingly apparent that the hormone has a much broader repertoire. Its functional variability is made possible by (i) different enzymatic routes for its generation, (ii) different receptors distributed in different tissues, (iii) different mechanisms for receptor regulation, and (iv) different signal transduction pathways. 3. This insight is the direct consequence of advances in pharmacology that led first to inhibitors of angiotensin converting enzyme and later to angiotensin II receptor antagonists. This review looks at the current status of angiotensin biochemistry and physiology and provides a basis for anticipation of future developments.