Metallothionein in the ovaries of laying hens exposed to cadmium.

The presence of metallothionein (MT) and its mRNA in the ovaries of laying hens is reported. In laying hens injected with cadmium (Cd), Cd accumulated in the follicle walls of the ovaries not in the follicle yolks. In the follicle walls, (Cd, Zn)-MT and its mRNA were found. This indicates that MT bound to Cd is biosynthesized in the follicle walls. We suggest that MT might play a role in sequestering Cd. On the other hand, zinc (Zn) was found in the follicle walls and yolks in the Cd-treated laying hens. The relationship between Zn and (Cd, Zn)-MT is also discussed.