Abstract
Serum angiotensin-converting enzyme (AT-converting enzyme) activity was measured in 30 patients with sarcoidosis in relation to their chest X-ray findings. Thirty patients with a diagnosis f sarcoiodosis, including 16 males and 14 females, ranged in age from 14 to 61 years. Sixteen patients were untreated and 14 patients were undergoing treatment.
Assay was performed using hippuryl-Histidyl-Leucine as substrate. The activity was expressed as nmol/ml/min of liberated hippuric acid.
The activity of this enzyme in normal subjects was 15±0.9nmol/ml/min. Serum AT-converting enzyme activity was significantly increased in patients with a sarcoidosis lesion in chest X-ray findings. The enzyme activity in untreated sarcoidosis patients was significantly higher than in normal subjects (38±2.3nmol/ml/min). As the chest X-ray findings improved, serum AT-converting enzyme activity became lower. The activities of the enzyme before and after improvement of the chest X-ray findings were as follows; 40.0±4.2nmol/ml/min and 27.8±1.8nmol/ml/min, respectively. Many patients showed higher activity of the enzyme than that in normal subjects even after improvement of chest X-ray. In cases of relapse, serum AT-converting enzyme activity increased again. The enzyme activity was decreased as the X-ray findings improved, with or without steroid treatment. It was concluded that the enzyme activity in patients had a more intimate relationship to the chest X-ray findings than to the administration of the steroids or other drugs. Though the mechanism of the elevation of this enzyme activity in sarcoidosis is not clear, the assay of the enzyme may be very useful for predicion of the course of this disease.
