Formation of metallothionein in fish.

1. Carp were bred in Cd solution, and each organ was homogenized and centrifuged at 105,000 g. The Cd content of the supernatant was much more than that of the precipitate. 2. In examining the metal form in the supernatant, the induction of metallothionein (MT) was found in carp exposed to Cd and Zn solutions and the presence of metallothionein was found in fish captured in Nagara river and breeding ponds. 3. Cd content in the metallothionein fraction of hepato-pancreas increased at the early stages of exposure, but Cd in the metallothionein fraction of the other organs increased as time proceeded. 4. In the tap water group, metallothionein in hepato-pancreas and kidney contained Cu, and increased with the induction of metallothionein in hepato-pancreas due to Zn-exposure.