[Renal glutaminase I activities in experimental and human chronic pyelonephritis (author's transl)]

Abstract

Question: For more exact knowledge on the pathogenesis of pyelonephritis a series of large scale histochemical and biochemical investigations were performed. In this study the author reports his observations on the renal glutaminase I activities in experimental and human pyelonephritis.

Materials and methods: Details on materials and methods were given in a recent paper [PHILIPPSON, Exp. Path. 8, 182-193 (1973)]. Glutaminase I activities (L-glutamine amidohydrolase, EC 3.5.1.2.) were quantitatively analyzed according to MATTENHEIMER and DEBRUIN (7) in which the reaction was not only produced by cooling but also by simultaneous inhibition by means of 15% trichloric acetic acid. Ammonia was released and determined by Berthelot's reaction as modified by WELLER (18).

Results: The results in rabbit kidneys are compiled in the tables 1-3, the observations on human kidneys are represented in table 4. 139 rabbits showed unilateral experimental pyelonephritis, in 19 rabbits pyelonephritis did not develop or "healed up spontaneously". 31 samples of pyelonephritic nephrocirrhotic human kidneys (obtained by surgical operations) and 20 samples of healthy human kidneys were investigated. After separation of renal cortex and medulla the cortex was separated into glomerula and renal tubules by differential centrifugation. Significance was tested by universal comparison of the group mean values by t-test (rabbit and human kidneys separately). 1. In the rabbit glomerula glutaminase I (glut I) activities were increased significantly from the beginning of the experiment up to 100 days. They decreased markedly in the subsequent nephrocirrhotic stage (fig. 1). 2. The glut I activities in the rabbit cortical tubules decreased immediately, intensively and succesively up to the late-chronic nephrocirrhotic stage. 3. The rabbit medullary glut I showed likewise intensive decrease in the acute and subacute phase progressing to very low activities in the nephrocirrhotic stages. 4. In all samples from human pyelonephritic nephrocirrhoses (glomerula, cortical tubules and medulla) extremely decreased glut I activities were demonstrated. 5. The enzyme activities observed and the results of the semiquantitative histological analysis [SORGER and co-workers, Exp. Path. 9, 280-287 (1974)] are closely correlated. 6. In the glomerula of the "spontaneously healed up" tissue the glut I activities were markedly increased whereas they were moderately decreased in the cortical tubules and in the medulla. 7. The dry weights and values of protein content were equal to those earlier reported (PHILIPPSON 1973). 8. In the significance test (universally applied t-test) the overwhelming majority of the values showed high significance (p less than or equal to 0.001). The results are correlated with the observations of the semiquantitative histological analysis (SORGER et al. 1974) and discussed on the basis of data reported in literature.