Proteinuria and nephrotic syndrome induced by renin in patients with renal artery stenosis.

Exacerbation of hypertension and a marked excretion of protein in the urine were observed in three patients in the absence of underlying renal parenchymal disease or other causes of proteinuria. Stenosis of a renal artery and hyperreninemia were present in all three patients. Correction of the stenosis by arterial bypass or nephrectomy resulted in a rapid decrease in urinary protein excretion. The relationship between the levels of renin activity and the proteinuria in one patient and long-term follow-up in the other two patients are reported, and the mechanisms of this proteinuria are reviewed. Renal artery stenosis may be the underlying cause in some cases of idiopathic nephrotic syndrome.