Observations on the localization of arylsulphatase activity in renal cortical tubules

Problems with ultrastructural demonstration of aryl sulphatase activity in rat liver parenchymal cells

The classical method for the electron microscopical demonstration of aryl sulphatase activity in lysosomes (Hopsu-Havu et al. 1967) has been applied for selective demonstration of lysosomes in rat liver parenchymal cells. A positive reaction was obtained in some lysosomes, but the greater part of the precipitate was found in the form of big conglomerates which frequently filled up the interstices between various organelles rather than that they were localized within the organelles. Modifications of the procedure in order to try to confine the demonstration of enzyme activity to lysosomes only included measures: To reduce the amount of primary reaction product, to improve the trapping efficiency of the incubation medium, to prevent possible displacement of the final reaction product. Extralysosomal precipitate persisted under all circumstances; this is interpreted as an artefact rather than as a demonstration of enzyme activity localized in vivo in the cytoplasmic matrix. It is concluded that the present method for demonstration of aryl sulphatase activity is not well suited for microscopical identification of lysosomes in rat liver parenchymal cells.

Soluble arylsulphatases in the rabbit salivary glands. A light and electron microscopy study

A histochemical study was effected, by light and electron microscopy, on the activity of arylsulphatases A and B in the submandibular and sublingual glands of male and female rabbits, distinguishing, among the latter, between the physiological estrus and anestrus condition. The results obtained demonstrated that the enzymatic activity is more intense in the sublingual gland and that the estrus condition causes an increase in this activity. No correlation was found between the topochemical distribution of the soluble arylsulphatases and that of sulphates.

[Distribution of some hydrolases in the rat kidney (author's transl)]

Most of the available histochemical methods and techniques (azodye, metal salt and indigogenic methods, cryostat, free-floating and lyophilized section techniques) and different modifications of these methods (different substrate concentrations, pH, temperature, incubation time e.g.) were applied to study the distribution of acid phosphatase (AcPB = after Barka and Anderson; AcPG = after Gomori), beta-glucuronidase (beta-Glu), aryl sulfatase (AS), beta-N-acetylglucosaminidase (NAG), acid 5'-nucleotidase (a5-Nucl), non-specific esterase (NE) and alkaline phosphatase (AlP) in the kidneys of rats of both sexes. The optimal conditions for the demonstration of these enzymes were established. As most important proved: the incubation of free-floating sections cut from "standard"-fixed (2 h in formol-calcium continued for another 18-22 h in the same fixative plus 0.88 M sucrose at 4 degrees C) kidney slices - only for AcPB and NE material fixed after Holt had to be used; the incubation for AlP and NE at 4 degrees C; final pH of the incubation medium for AcPB 5.5, AcPG 5.0 and NE 6.5; the use of Fast Garnet GBC Salt as coupler in the NE azo-dye reaction. Sex differences and for the female rats an increased activity during oestrus were established for all hydrolases studied. In particular the following results were obtained: AcPB, a5-Nucl and A1P are more intensive in male and AcPG in female S1 segments of the juxtamedullary nephrons in relation to the nephrons of the other parts of the cortex. In the medullary rays the NE and the a5-Nucl show a higher activity in the S2 segments of female rats demonstrate a more intensive activity for NAG and NE. This is true for AcPG and A1P in male rats. In the inner medulla a stronger beta-Glu activity in male rats and a stronger NAG activity in female rats is observed. The AcPB activity of the cortical distal tubules is higher in male rats.

Lysosomal enzymes in the juxtaglomerular cell granules

In addition to the already known acid phosphatase and beta-glucuronidase, 2 other lysosomal enzymes: aryl sulphatase and N-acetyl-beta-glucosaminidase were localized by histochemical methods in the renin-containing granules of the mouse juxtaglomerular cells.