The influence of prednisone on serum angiotensin-converting enzyme activity in patients with and without sarcoidosis.

The influence of prednisone on S-angiotensin-converting enzyme (SACE) activity was examined by serial measurements in 20 non-sarcoidosis patients and 8 sarcoidosis patients on prednisone, compared with 26 patients and healthy controls not under treatment. All but the sarcoidosis patients had SACE within normal limits (12.0-36.8 kU/l). In the three groups initial or pretreatment SACE levels (mean +/- SD) were 20.1 +/- 5.7, 66.9 +/- 27.4 and 26.4 +/- 4.1 kU/l, respectively. Non-sarcoidosis patients on prednisone had a lower pretreatment SACE than untreated control persons, presumably due to the different diseases represented in the groups. During the observation period SACE was rather stable in untreated patients and also in the treated group as a whole. But in 12 patients with SACE greater than 18.2 kU/l (mean of reference series minus 1 SD) a significantly decreasing SACE was observed after 1 week of treatment, whereas SACE was unchanged in patients with lower pretreatment levels, suggesting that in these patients prednisone could not decrease any further a level which was already low. In sarcoidosis the elevated SACE declined, reaching a normal level after 4 weeks on prednisone. In the assay ACE was markedly inhibited by SQ 14,255 (Captopril), moderately by methylprednisolone in concentrations exceeding those generally used clinically, while no inhibition was seen using acetylsalicylic acid.