When a solution of zinc sulfate was injected to rat subcutaneously at a dose of 20 mg Zn/kg, the concentration of metallothionein in the pancreas reached the maximum value 36 h after the administration and then decreased with an apparent half-life of 30.9 h. Therefore, Zn-thionein-I and -II were purified by use of gel filtration on Sephadex G-75 and DEAE-cellulose chromatography, from the pancreas of rat given with ten times of subcutaneous injection of a solution of Zinc sulfate at a dose of 20 mg/kg every 24 h. These samples were found to be homogeneous by disc electrophoresis. The results of their absorption spectra and amino acid analyses have the characteristics of Zn-thioneins. From these results the synthesis of Zn-thioneis which resembles metallothionein in the liver was shown to be induced in the organs by the administration of Zn.
