HISTOCHEMICAL INDICATIONS FOR LYSOSOMAL LOCALIZATION OF HEAVY METALS IN NORMAL RAT BRAIN AND LIVER

Abstract

With a modified sulfide-silver method for the demonstration of heavy metals, hepatic parenchymal cells, Kupffer cells, neurons and glial cells were found normally to contain stainable cytoplasmic granules with a shape, size and distribution identical with that of lysosomes in the various cells studied. Previous studies have shown the lysosomes of mast cells and eosinophilic leukocytes normally to contain zinc. Iron has also been demonstrated in residual bodies in different tissues. Under pathologic conditions, such as Wilson's disease and experimentally induced intoxications, lysosomes have been shown to take up copper, mercury and lead. Our results suggest that heavy metals are normal constituents of lysosomes in a more general way than hitherto assumed.