Podocytes in aminonucleoside glomerulonephritis investigated ultrastructurally with concanavalin A

Peroxidase labeled concanavalin A (Con A) permits the detection of some saccharide determinants. This histochemical technique permits the visualization of cellular pathological modifications not observed with other methods. Its use in an ultrastructural study of nephritis induced by a single injection of aminonucleoside demonstrated the following in podocytes. The Con A positive endoplasmic reticulum (ER), essentially the rough ER, lost its normal linear and network appearance to take on a dot dash pattern. ER contents but not attached ribosomes and membranes were Con A positive. The dot dash pattern, due to a fragmentation of the ER, appeared prior to the onset of proteinuria and was attenuated before the disappearance of proteinuria. These changes of the ER were not observed in other proteinuric states. This suggests that aminonucleoside can damage the synthesis apparatus of podocytes, revealed by the Con A method.