Abstract
Although various hypotheses have been proposed about the ultrastructure of the glomerular basement membrane (GBM) of the kidney, it has not clearly revealed. At present, it is thought to be composed of a meshwork of fibrils as reported by Ota et al. We successfully observed the meshwork structure of the GBM under an electron microscope after enzymatic treatment with α-amylase and elastase. The fibrils were about 30 nm in width and were thought to be composed of type IV collagen.