Abstract
Formation of the glomerular basement membrane in developing human renal glomerulus is observed, and experimentally the metabolism of lamina densa in normal and nephrotic rats are investigated by means of electron microscopy. 1) In immature glomeruli, two components, that is, epithelial and mesangial take part in formation of the glomerular basement membrane, and the double-membrane structures are observed. 2) In normal rats, the basement membrane is maintained itself in constant thickness, as keeping balance of the formation of new fibrils and the destruction of old ones. The turn over of the base-ment membrane component is mainly taken place from the epithelial surface. 3) Glomerular basement membrane has extremely and variably thickened in nephrotic rats, and there are two ways of new formation of the basement membrane, the one from epithelial and the other mesangial side. Histological changes can be divided into following two types.1. Formation from epithelial side and destruction on endothelial side are increased in violence si-multaneously, and then the original lamina densa is replaced rapidly with new increment.2. Formation from both epithelial and mesangial side are enhanced, and the original lamina densa has its location just as sandwiched by new increment. 4) There could be found no any correlations between the fusion of foot processes and the formation of glomerular basement membranes, however, it is suggested that dense material in the epithelial cell may produce new lamina densa.
