Basement membrane heparan sulfate proteoglycans are concentrated in the laminae rarae and in podocytes of the rat renal glomerulus.

A polyclonal antibody was raised against a proteoglycan fraction purified from extracts of isolated rat renal glomeruli. The antibody was characterized by column chromatography and by NaDodSO4/PAGE analysis of immunoprecipitates and was shown to recognize specifically the core protein of a population of heparan sulfate proteoglycans (Mr 130,000) found in the glomerular basement membrane and in other renal basement membranes. The antibody was used to localize the core proteins of this population of heparan sulfate proteoglycans (HSPG) in the glomerulus by immunoelectron microscopic techniques. These HSPG were found to be concentrated in the lamina rarae interna and externa of the glomerular basement membrane (GBM) and precursor forms were detected in the endoplasmic reticulum and Golgi cisternae of glomerular visceral epithelial cells (podocytes).