OBJECTIVES: 1. Evaluation of new renin-angiotensin inhibitors. 2. Characterization and modulation of the sequence of biochemical events during the angiotensin-receptor reaction leading to prostaglandin (PG) biosynthesis and AII tachyphylaxis. 3. Investigation of the site, mechanism, and importance of angiotensin heptapetide (AIII) stimulation of prostaglandin release and investigation of new AIII analogs which might be more potent, longer lasting and more specific.