Circulating factor with ouabain-like immunoreactivity in patients with primary aldosteronism.

Circulating factor with ouabain-like immunoreactivity was studied in patients with primary aldosteronism. Anti-ouabain antibody was prepared from specific pathogen-free rabbits. In the plasma of patients with primary aldosteronism, the level of a factor with ouabain-like immunoreactivity was 2.59 +/- 1.39 pmol ouabain equivalent/ml plasma. This value was significantly (p less than 0.05) higher than that of age-matched normotensive subjects, 1.06 +/- 0.86 pmol ouabain equivalent/ml plasma. The plasma level of ouabain-like immunoreactivity correlated significantly (p less than 0.05) with blood pressure. These results indicate that the factor with ouabain-like immunoreactivity may play a pathophysiological role in the maintenance of the high blood pressure observed in patients with primary aldosteronism.