The effect of long-term treatment with spironolactone on sodium pump abnormalities in the red blood cells of patients with Bartter's syndrome.

To elucidate the possible sodium transport alterations across the cell membranes in Bartter's syndrome and their influencing by spironolactone treatment Na+-K+-ATPase activity was studied by means of radioactive 86Rubidium influx into red blood cells (RBC) of patients with Bartter's syndrome prior to and after a long-term spironolactone administration. As compared with the control subjects and patients with primary aldosteronism the patients with Bartter's syndrome had a more than 5 times higher 86Rb uptake by the RBC, especially in the ouabain-sensitive component. A long-term spironolactone treatment led to the decrease of this high influx. Serum of patients with Bartter's syndrome incubated with healthy RBC distinctly increased their 86Rb influx. The increase nevertheless did not reach the values in the RBC of untreated patients with Bartter's syndrome. Even if our results do not allow to explain fully the mechanism responsible for the Na+-K+-ATPase changes in the RBC of these patients, analysis of the studied parameters demonstrated that none of the known humoral factors as aldosterone, renin, prostaglandins, or changes of the serum potassium were responsible for these abnormalities. The changes of sodium transport in RBC of patients with Bartter's syndrome could be a part of a more general disturbance of the transport mechanism and could significantly participate in the pathogenesis of this disease.