COMPARATIVE HISTOCHEMICAL LOCALIZATION OF LYSOSOMAL ENZYMES IN RAT TISSUES

Abstract

Localization of acid phosphatase, β-glucuronidase and N-acetyl-β-glucosaminidase has been studied in various tissues of the rat with comparable simultaneous coupling azo dye techniques employing naphthol AS-BI compounds as substrates and hexazonium pararosanilin as a capture reagent. These three lysosomal hydrolases were widely distributed in tissues and were generally demonstrated as discrete granules in certain portions of the cytoplasm. Granules stained for each enzyme were localized at identical sites in most, but not all, tissues in which they were present. However, the intensity or number of granules stained for each of the enzymes was found to differ in varying degree among tissues. Acid phosphatase appeared to be more widespread in tissues than the two glycosidases. Distribution of the glycosidases was also found to differ considerably. Cells of the macrophage system, for example, displayed high β-glucuronidase activity, while N-acetyl-β-glucosaminidase was much less active in these cells. The latter enzyme was more active in the epithelium of the mucous membrane. Furthermore, in several tissues, the three enzymes exhibited qualitatively different localization. In these sites, one or two of the enzymes were not or were only faintly demonstrable while the other showed an intense reaction. These findings suggest that a functional differentiation among lysosomes in various tissues may exist.