Half-life of angiotensin II in the conscious and barbiturate-anaesthetized rat

The half-life (T 1/2) of angiotensin II was measured in rats with chronic indwelling catheters. In conscious animals T 1/2 was 14.8 +/- 2.5 s; during anaesthesia T 1/2 increased by 60%. Anaesthesia decreased the control arterial pressure, but did not alter the sensitivity to injected angiotensin II. The causes and consequences of this change in angiotensin catabolism are discussed.