Comparative ultrastructural cytochemistry of juxtaglomerular cell granules and renal tubular cell lysosomes

Abstract

Because of certain similarities in morphology and function between juxtaglomerular cell granules and renal tubular cell lysosomes, the cytochemistry of both of these structures was compared. Juxtaglomerular cell granules and renal tubular cell lysosomes were found to be argentaphobic when ultrathin sections of Araldite-embedded kidneys were stained according to the periodic acid-thiocarbohydrazide-silver proteinate technique of Thiéry (Thiéry, J. P. J. Microsc. (Paris) 6: 987, 1967 and J. Microsc. (Paris) 8: 689, 1969). The rim of both structures was moderately positive when ultrathin sections of glutaraldehyde-fixed, glycol methacrylate-embedded kidneys were stained with phosphotungstic acid at a low pH. A reaction was also shown by the cell coats, residual bodies and, in proximal convoluted tubules, by the Golgi complex. In ultrathin sections of either glycol methacrylate- or Vestopal-embedded renal cortex stained by various methods with colloidal iron, juxtaglomerular cell granules were negative whereas renal tublar cell lysosomes were intesely positive. Colloidal iron also stained the cell coats of both justaglomerular and tubular cells. These results indicate that both juxtaglomerular cell granules and renal tubular cell lysosomes contain glycoproteins which are not acidic in the former and are acidic in the latter.