Biochemical studies of the isolated rat glomerulus and the effects of puromycin aminonucleoside administration.

Using analytical subcellular fractionation techniques in combination with enzymic microanalysis, studies have been performed on the enzymology and organelle pathology of isolated glomeruli from normal rats and from animals with puromycin aminonucleoside nephrosis. There was a marked decrease in 5'-nucleotidase (plasma membrane) activity 2 days after puromycin aminonucleoside administration. In contrast, catalase (peroxisomes) and N-acetyl-beta-glucosaminidase (lysosomes) showed a significant rise during the first 6 days of treatment. By 10 days most marker enzymes showed a significant decrease in activity. The glomeruli were homogenized in isotonic sucrose and extracts were fractionated by isopycnic centrifugation on linear sucrose gradients in the Beaufay automatic small-volume zonal centrifuge. The properties of the principal organelles were characterized. ed. After 10 days of puromycin aminonucleoside treatment there were no marked differences in the centrifugal properties of these organelles. Morphological correlations with the biochemical changes are discussed and it is suggested that the plasma membrane changes represent the primary site of puromycin aminonucleoside damage.