Daily subcutaneous injection of twelve kinds of metal into rats were carried out for one, two or four days at a dosage of 10 mg per kg. After measuring the concentrations of metallothionein and metals in four kinds of organ, the following results were obtained. 1) The apparent inducibilities of metallothionein by Co and Ni in the liver were almost the same as that by Zn. Those by Ca and Mn were 0.44 and 0.36 times that of Zn, respectively. By the administration of Al, Cr, Fe, K, Mg, Na or Pb no significant increase in the concentration of metallothionein in the liver was detected. 2) The apparent inducibility of metallothionein by Ni in the kidney was about twice that by Zn. Co also had a weak apparent inducibility. No other metals used in this experiment increased the concentration of metallothionein in the kidney. 3) Metals other than Zn examined did not induce metallothionein in the small intestine and pancreas. 4) Although a positive correlation was detected between Zn and metallothionein concentration in the organs when metallothionein was induced, between metals administered and metallothionein concentration in the organs a positive correlation was not always given.
