Electron Microscopic Demonstration of Nonspecific Esterases in the Small Intestine of the Rat

Abstract

The nonspecific esterase activity was investigated at the electron microscopic level, by means of azo dye technique applied to the duodenal, jejunal and ileal mucosae of living rats. After perfusion of a medium containing 1-naphthyl acetate and hexazonium pararosaniline into the lumen of the small intestine, the enzyme reaction product of electron opaque grains (50-100 nm in diameter) was localized on the limiting membrane of microvilli of epithelial cells, and on the vesicles and the granular endoplasmic reticulum in the apical cytoplasm of epithelial cells. When the medium was perfused intravascularly, electron opaque grains were localized on the basal cell membrane and the basal lamina of epithelial cells as well as on the vesicles present in the basal cytoplasm of epithelial cells. Localizations of the esterase activity were essentially alike whether naphthyl propionate or butyrate was used as a substrate.The esterase activity in the duodenal and jejunal mucosae was higher than that in the ileal mucosa, judging from the results of inhibition test and reactivation test.In earlier histochemical works using the light microscope, Gomori (1945Gomori ( , 1948 reported occurrence in the mucosa of rat small intestine of the nonspecific esterases as demonstrated by means of Tween's method. Since then, contributions have been made in the field of nonspecific esterase histochemistry for the development of azo dye technique by

Histochemical Study of Non-Specific Esterase Activity in the Liver, Kidney and Small Intestine From Nine Different Mammalian Species

“…Although its specificity is somewhat less than other substrates such as 5-bromoindoxyl acetate (2) and naphthyl acetate (18), the reaction occurs directly and in a single step. Wachstein et al (17) have demonstrated with light microscopy that the distribution patterns of esterase detected with thiolacetic acid were comparable to those of napthhol-AS and 5-bromoindoxyl acetate substrates.…”