Glomerular podocyte cell junctions in nephrotic syndrome. I. Freeze-fracture studies in rat aminonucleoside nephrosis.

Aminonucleoside nephrosis was induced in rats after a single i.p. injection of puromycin aminonucleoside (PAN). Freeze-fracture studies of the glomeruli were done, three, six and ten days after PAN injection. The epithelial filtration slits disappeared six days after PAN injection. On the split plasma membrane of the podocytes three types of cell junctions which apparently were newly formed were seen: 1) single strands (occluding junctions of leaky type); 2) networks of limited extent, composed of strands and particles (maculae occludentes); 3) assemblies of particles or pits (maculae communicantes) connected by single strands. The cell junctions of podocytes were comparable with those found in human nephrotic syndrome. (Kühn et al., 1981).