Role of aldosterone in the sodium retention of patients with nephrotic syndrome.
The role of aldosterone in the abnormal sodium retention in patients with nephrotic syndrome has been debated. In fact, studies using a converting enzyme inhibitor to lower plasma aldosterone have rejected such a role. We therefore studied 5 nephrotic patients and 6 control subjects by using the more specific aldosterone antagonist, spironolactone. After withdrawal of diuretics 5 days prior to the study, the nephrotic patients and control subjects were placed on a high-sodium diet (285 +/- 6 mEq/day) for 8 days. After 4 days, spironolactone 200 mg p.o., b.i.d., was given for the remaining 4 days. Plasma renin activity and plasma aldosterone levels were similar in both nephrotic patients and control subjects before the study, after sodium loading and after spironolactone had been given. After 4 days of high sodium intake control subjects were in sodium balance, but the nephrotic patients were in a positive sodium balance (approx. 80 mEq/day; p less than 0.01). On days 3 and 4 of spironolactone, the nephrotic patients exhibited an increase in urinary sodium excretion (205 +/- 20 vs. 312 +/- 13 mEq/day; p less than 0.005) but not the control subjects (279 +/- 16 vs. 286 +/- 13 mEq/day; NS). It is therefore concluded that aldosterone is a significant contributor to the sodium retention in patients with nephrotic syndrome.