Angiotensin II: its metabolic fate.

Randomly labeled tritiated angiotensin has been prepared with a specific activity of 300 microc/mg and with undiminished pressor and oxytocic activity. After infusion, angiotensin accumulated in the kidneys, adrenal glands, and uterus. Thirty minutes after infusion high levels of radioactivity appeared in brain, but the electrophoretic mobility differed from that of angiotensin II. Incubation of angiotensin with hemolyzed human red blood cells or diluted human plasma rapidly inactivated the pressor activity with production of metabolic products separable by paper chromatography. But if undiluted plasma is used with incubation up to 6 hours, no loss of activity occurs.