Histochemical studies on the mechanism of macromolecule leakage across the glomerular capillary wall. Barrier effect of the anionic groups of the capillary wall against the serum protein leakage

For the purpose of revealing the barrier effect of the anionic groups of glomerular capillary wall against the serum protein leakage, morphologic and histochemical observations were made on the rat kidney perfused in situ with three kinds of cationic macromolecules different in chemical characteristics followed by blood flow restoration. The polyethyleneimine perfusion resulted in the complete disapperance of ionized anionic groups of glomerular capillary and the massive protein leakage through glomeruli by blood flow restoration. Cationic ferric colloid perfusion induced moderate protein leakage, and avidin perfusion was less in neutralization effect of anionic groups and the protein leakage was of least. The protein leakage from glomeruli, however, was stopped or markedly suppressed soon after the blood flow restoration by the newly formed functioning anionic barrier probably by some particular serum protein deposition. The findings indicate that the deionization of the glomerular capillary wall will not be responsible for the persistent albuminuria.