Increased activity of the Na-K-ATPase in red cell-ghosts of patients with Cushing's syndrome: possible significance for the pathogenesis of glucocorticoid-induced hypertension.

The Na-K-ATPase activity of erythrocyte ghosts was increased in 6 patients with Cushing's syndrome compared with 28 control subjects (0.986 +/- 0.291 versus 0.259 +/- 0.1 microM Pi . h-1 . mg-1, p less than 0.001). Ouabain insensitive Mg-ATPase activity was similar in both groups. These data support the concept of an activation of the Na-pump in patients with glucocorticoid excess.