Subcellular distribution of metallothionein and cadmium in the liver and kidneys of bank voles (Clethrionomys glareolus) exposed to dietary cadmium

Metallothionein (MT) and cadmium (Cd) contents were determined in the subce llular fractions of the liver and kidneys of bank voles exposed for 6 weeks to elevated levels of dietary Cd-40 and 80 mu g g(-1) dry weight. Hepatic and renal MT was detected exclusively in the cytosol, while Cd was found in the cytosol (73-79% of the total content), nuclei (14-18%) and particulate s (4-9%). The concentration of MT in the cytosol as well as Cd content in t he particular subcellular fractions appeared to be a dose-dependent. The ab sence of MT in the nuclear and particulate fractions implied that Cd presen t in these compartments was not bound to the protein that is considered to provide protection against the toxic metal. Therefore, it is assumed that t his component of intracellular Cd could be responsible for the histopatholo gical changes that occurred in the liver (granuloma and focal hepatocyte sw elling) and kidneys (focal degeneration of proximal tubules) of bank voles exposed to the higher level of dietary Cd.