Captopril (Tenziomin) treated rats after subtotal (5/6) nephrectomy showed conspicuously better function of kidney tissue remnants than untreated animals. Histology was the same in both groups--focal glomerulosclerosis, anisocytosis and anisokaryosis of tubular epithelial cells, hyperplasia of proximal tubuli. Proteinuria was substantially lower in treated animals. Lectin histochemistry showed differences between superficial and juxtamedullary nephrons in glycoprotein contents and function. An important finding was selective binding of WGA lectin in brush border of proximal convoluted tubuli of juxtamedullary nephrons. Differences in lectin binding between nephrectomized and intact control animals were rather quantitative than qualitative.