[The effects of human and mouse pepsins on Masugi nephritis].

The effects of intravenous administration of human or mouse pepsin were investigated on Masugi nephritis in rats and mice, which is an experimental model of glomerulonephritis in humans. Injection of anti-kidney serum to rats significantly increased the urinary protein excretion, serum levels of fibrinogen, cholesterol and immune complex, significantly decreased serum immunoglobulin G and complement levels, and caused histopathological changes such as detachment of endothelial cells from basement membrane, thickening of basement membrane, fusion of foot process and increase in hyaline cast in renal tubuli. Deposit of anti-rat IgG on glomerular capillary wall was also observed. All of these changes were ameliorated or showed a tendency to be ameliorated by intravenous administration of human pepsin, and the mechanism responsible for these effects was suggested to be selective decomposition of immune complex. Marked increase in urinary protein excretion was also observed in mice that intravenously received anti-kidney serum. This increase was suppressed by intravenous administration of human or mouse serum, the latter showing a stronger effect.