Is the Renin-Angiotensin-Aldosterone System Involved in the Sodium Retention in the Nephrotic Syndrome?

12 patients with the nephrotic syndrome during a phase of spontaneous sodium retention were studied on a sodium balance. When retaining sodium and gaining weight for more than 3 days, 6 patients had an elevated plasma renin activity; plasma aldosterone was elevated or at the upper range of normal, and blood volume was less than predicted in 5. The other 6 patients had a low or normal plasma renin activity and plasma aldosterone; blood volume was greater than predicted in 5 of these patients. There was a significant inverse correlation between plasma albumin and plasma renin activity (r = -0.70, p less than 0.02). Thus the renin-angiotensin-aldosterone system is not stimulated in many patients with the nephrotic syndrome when spontaneously retaining sodium. In these patients, sodium retention is probably due to some other mechanism, possibly intrarenal. Stimulation of the renin-angiotensin-aldosterone system in other patients may be a compensatory mechanism to the lower plasma albumin and reduced blood volume, and may not be the underlying mechanism for sodium retention.