REDUCED RETENTION OF CADMIUM IN THE LIVER OF METALLOTHIONEIN-NULL MICE

The distribution of cadmium (Cd) in the organs of mice was studied usi ng metallothionein (MT)-null transgenic mice. When mice were administe red with Cd chloride at a single subcutaneous dose of 1.0 mg Cd/kg bod y weight, Cd accumulated mainly in the liver and kidney by 6 h after i njection without any significant difference between the MT-null mice a nd control (C57BL/6J) mice. MT was not detected in these or ans of MT- null mice both before and after Cd administration whereas MT was induc ed mainly in these organs of the control mice. Then was a marked elimi nation of Cd from the liver of MT-null mice by 21 days after administr ation, compared with a relatively slow Cd elimination in the C57BL/6J mice. Under the condition that no significant liver or kidney damage w as observed, MT was considered to play a significant role in the reten tion of Cd in the liver but not in the uptake of this metal.