QUANTITATIVE HISTOCHEMISTRY OF THE KIDNEY. II. ENZYMATIC ACTIVITIES IN GLOMERULI AND PROXIMAL TUBULES IN AMINONUCLEOSIDE NEPHROSIS IN RATS

Abstract

Quantitative determinations of enzymatic activities in glomeruli and in two segments of proximal tubules at intervals in the development of aminonucleoside nephrosis in rats suggest that several mechanisms are at play in this experimental disease. Increased glucose-6-phosphate dehydrogenase in glomeruli, first demonstrated by Dubach and Recant, and increased 6-phosphogluconic dehydrogenase in glomeruli were the earliest enzymatic alterations which were demonstrated and constitute evidence that the glomerulus is the renal structure primarily deranged in this form of experimental nephrosis. The exact biochemical nature of the glomerular lesions remains obscure. Decreased tubular alkaline phosphatase was correlated with tubular dilatation from obstruction by casts. Decreases were found in tubular activities of malic, glutamic, and isocitric dehydrogenases, and of glycylphenylalanine dipeptidase; similar changes in these activities were observed in experimental proteinuria. In aminonucleoside-treated animals, slight increases in glomerular malic, lactic, and glutamic dehydrogenases occurred after 11 to 15 days, appreciably later than the increases in enzymes of the hexose monophosphate pathway. Increased tubular activity of acid phosphatase may be a component of non-specific cellular degeneration.