Postnatal changes in subcellular distribution of copper, zinc and metallothionein in the liver of bank vole (Clethrionomys glareolus): a possible involvement of metallothionein and copper in cell proliferation.

1. Dramatic interdependent changes in the intracellular concentrations of copper (Cu), zinc (Zn) and metallothionein (MT) in the liver of bank voles during the first 30 days of their life were observed. 2. The post-mitochondrial Cu, Zn and MT (Zn-MT) abruptly decreased between 1 and 3 days following birth but the nuclear MT (Cu-MT) and Cu increased at the same time, suggesting that Cu displaced Zn already bound to MT in the cytoplasm and subsequently the complex Cu-MT was translocated to the nuclei. 3. The nuclear Cu concentration reached the highest level (62-71% of the total tissue Cu) in the period from day 3 to day 20 post-partum, just prior to and during a rapidly growing liver. 4. The data indicate that MT and Cu may be involved in the hepatocyte proliferation.