The effect of methotrexate (MTX) on the small intestine of the mouse. IV. The Golgi apparatus, phosphatases and esterases.

The Golgi apparatus and alkaline and acid phosphatase and nonspecific esterase activities were studied in the jejunal epithelium of adult male albino mice (Mus musculus) under normal conditions and after MTX treatment. In the control, the Golgi apparatus took the form of rods, spheres and crescents occupying the supranuclear region. After MTX, the Golgi apparatus, in most of the cells, was hypertrophied. In the control cells, alkaline and acid phosphatase and nonspecific esterase activities were moderate and localized supranuclearly, but were intense in the brush border and basement membrane. After MTX, all three enzyme activities increased, with a marked reaction in the brush border and basement membrane. The increase in alkaline phosphatase may mean that more phosphate transport is needed in the active phosphorylation process or in the transfer of MTX macromolecules across the cell membrane, or it may be due to MTX-induced disorganization of metabolism. The increase in acid phosphatase activity denotes an increase in catabolic processes resulting from imbalance of lysosomal function, while the rise in nonspecific esterase activity could be related to fatty acid metabolism, or it might be due to the detoxicant function of esterases. In all control and MTX-treated specimens, the supranuclear concentration of these enzymes coincided with the localization of the Golgi apparatus.