Albumin Absorption by Renal Proximal Tubule Cells

IT is widely accepted that different types of foreign proteins are absorbed by renal proximal tubule cells when present in the glomerular filtrate. Very little is known, however, about the way in which proximal tubules handle serum proteins, although these may be present in the proximal tubule fluid under both normal1,2 and pathological conditions. The present experiments were carried out to determine whether homologous serum albumin can be absorbed by proximal tubule cells and, if so, to determine by means of autoradiography at the electron microscopical level which cellular components participate in the absorption.