[Ultrastructural study of the glomerular filtration barrier and of tubular reabsorption with anti-peroxidase antibodies and their fragments].

Using anti-peroxidase Sheep IgG or their pepsic or papainic fragments intravenously injected to Wistar Munich normal Rats, the glomerular filtration barrier was localized at the lamina densa in ultrastructural studies. No evidence was found favoring the existence of a second barrier. The filtration barrier is absolute for the IgG but not for the pepsic and especially the papainic fragments which are reabsorbed by the proximal tubule.