The ultrastructural localization of metallothionein in cadmium exposed rat liver.

The ultrastructural localization of metallothionein (MT) was investigated in the liver of male Wistar rats by a cryo-immunocytochemical technique. The liver parenchymal and sinusoidal cells were studied in both cadmium-exposed (3 x 1.2 mg kg-1 as cadmium chloride) and non-treated animals. Treatment with cadmium induced the synthesis of MT yet differences in the distribution were evident amongst the various types of liver cell. MT was found most abundantly in the parenchymal and endothelial cells, yet was absent in the stellate cell and sparsely distributed in the Kupffer cell. In the cells where MT gene expression was induced, the metalloprotein was distributed within both the nuclear and cytoplasmic compartments. The significance of the nuclear localization of MT is discussed.