Significance of renal kininases in patients with primary aldosteronism.

To elucidate the significance of renal kininases in primary aldosteronism (PA), urinary total kininase, kininase I, II and neutral endopeptidase 24.11 (NEP) were examined and evaluated for the regulation mechanisms of these kininases. Total kininase, kininase I and NEP were significantly higher in PA than in normotensives (NT), whereas no difference was found for kininase II. Moreover, 42% of total kininase consisted of unknown kininase(s), different from kininase I, II or NEP. There were significantly positive correlations between plasma aldosterone concentration and total kininase, kininase I and unknown kininase(s) in PA. After the adrenalectomy, urinary kininases decreased into normal ranges, and unknown kininase(s) were negligible. These findings suggested that: 1) kininase I and NEP are accelerated in PA; 2) unknown kininase(s) differing from kininase I, II or NEP may exist in PA; 3) mineralocorticoids may regulate renal kininases; and 4) accelerated renal kininases may play some role in disorders of the renal water-sodium metabolism and in high blood pressure in PA.