Advances in molecular medicine and pharmacology have allowed clinician
s to critically reassess the renin-angiotensin system. Angiotensin II
(AII) participates in the control of cardiovascular function and elect
rolyte balance, and plays a part in the regulation of cellular oncogen
es and the expression of growth factors. The expression of the protein
s of the renin-angiotensin system in organs other than the kidneys sug
gests that these diverse actions are associated with the peptide in th
e local environment. Tissue renin-angiotensin activity has prompted th
e investigation of alternate pathways for the production of AII and ch
aracterization of novel forms of angiotensin peptides that counteract
the vasoconstrictor and proliferative actions of AII. The heptapeptide
angiotensin-(1-7) appears to be critically involved in regulating the
angiotensinogen activity of AII through stimulation of vasodilator pr
ostaglandins and release of nitric oxide. Study in this area has been
accelerated by the identification of receptors that convey the actions
of angiotensin peptides at the cellular level and the pharmacologic c
haracterization of agents that inhibit the ability of AII to bind to t
arget receptors. The introduction of a new class of orally active AII-
receptor blockers has provided a specific test of the role of AII in t
he development of essential hypertension and the potential for improve
d therapy for hypertension and cardiac and vascular sequelae.