Abstract
Distribution and form of radioactive cadmium in the metaphyseal bone of a rat femur were examined after intraperitoneal administration of 109CdCl2, and the following results were obtained. 1) Radioactivity was found mainly in the state bound to high molecular compounds in the 105000×g supernatant fraction of the bone. 2) These cadmium-bound high molecular compounds were fractionated sequentially by Sephadex G-75, G-100, and DEAE-cellulose columns, and were compared with metallothionein in the kidney. As a result, these compounds were very similar to metallothionein in points of the charge and molecular size. 3) From the in vitro experiments on binding, it was found that these compounds were induced after administration of cadmium.
