An altered relation between arterial pressure and plasma angiotensin II concentration resulting from prolonged infusion of angiotensin II.

1. Infusion of angiotensin II into dogs at constant dose over 2 weeks caused a progressive rise in arterial pressure. 2. When the infusion was stopped the pressure dropped slowly from hypertensive levels over 48 h. 3. Dose-response studies at weekly intervals showed progressive elevation, without steepening, of the plasma angiotensin II-blood pressure curve. 4. Thus, during prolonged administration of angiotensin II, a given plasma concentration of the peptide can sustain a higher arterial pressure than it can during acute infusions.