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 reabsorpti on through renal tubular cells. 2. These physiological functions have been appreciated for some time, but as details of the molecular and ce ll biology of the angiotensin response mechanism became understood, it is increasingly apparent that the hormone has a much broader repertoi re. Its functional variability is made possible by (i) different enzym atic routes for its generation, (ii) different receptors distributed i n different tissues, (iii) different mechanisms for receptor regulatio n, 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 I I receptor antagonists. This review looks at the current status of ang iotensin biochemistry and physiology and provides a basis for anticipa tion of future developments.