Serum angiotensin converting enzyme activity in human bronchial asthma

Using hippuryl-L-histidyl-L-leucine as a substrate analog, serum angiotensin converting enzyme (ACE) was spectrophotometrically estimated in patients with bronchial asthma. There were significantly low activities of serum ACE in 115 patients with bronchial asthma irrespective of the presence or absence of acute attack. The activity of serum ACE was reduced more markedly in the chronic type of bronchial asthma than in the paroxysmal type.