Decrease in the sialoglycoprotein content of the glomerular basement membrane in experimental nephrosis.

Phosphotungstic acid at low pH on glycolmethacrylate sections allows the detection of sialic acid groups in the lamina rara externa of the glomerular basement membrane. This staining procedure was used to study the alterations in puromycin aminonucleoside nephrosis and adriamycin nephrosis. In both model systems defects were detected in the sialic acid content of the lamina rara externa and the epithelial cell coat was also affected. The possible role of sialic acid in glomerular filtration is discussed.