Fine Structural Localization of Lysosomal Enzymes in the Absorbing Cells of the Duodenal Mucosa of the Mouse

Some enzymatic activities of lysosomes have been localized, wi th histochemical techniques applied to l ight microscopy, as fine granular deposits in the absorbing cells of the intestinal mucosa (1, 19). Barka (2), wi th the electron microscope, showed, in the cells of the duodena l villus of mouse, tha t acid phosphatase activity was confined to the dense bodies, the muhives icular bodies, and some Golgi vesicles. We obta ined identical results in the stem cells of the duodenal crypt (10). Two other enzymatic activities related to the lysosomes can be located by electron microscopy, i.e. those of arylsulfatase and E-6001-resistant esterase, considered by some authors as p robably cathepsin C (6). Moreover, alkaline phosphatase activity has been demonst ra ted in various types of dense bodies and mult ivesicular bodies of the absorbing cells of the d u o d e n u m of the mouse (12). Owing to the heterogeneity of these bodies, we have studied the fine s tructural localization of three lysosomal enzymes in this tissue, in order to identify more accurately these alkaline phosphatase-positive dense bodies as lysosomes.