Intracellular sites of toxic metals.

In summary, this brief overview of the cellular localization of toxic metals in renal tubular cells demonstrates a spectrum of mechanisms for the sequestration of the metals. Common features are affinity for a metal-binding protein, such as insoluble acidic nuclear proteins or the soluble, low-molecular weight metallothionein. Accumulation in lysosomes follows assimilation of metal containing protein by lysosomes or autophagocytosis of degenerating metal containing mitochondria. Currently available methods have not demonstrated the presence of metals in immune complex deposits in glomerular basement membrane and epithelial cells. The principal methods employed for the localization of metals within cells have been X-ray microanalysis of thin preparation of tissue, or direct analysis of subcellular fractions by atomic absorption spectroscopy or detection of radioactive metal.