Abstract
Progressive distribution of 115mCd in the blood and the main 115mCd-binding protein in the red cells were investigated after a single intraperitoneal administration of 115mCd-Cl2 to rabbit. 115mCd in blood decreased drastically on the 1st day after injection and increased sharply again on the 2nd day, then gradually decreased showing the regression equation of Y=-0.019x+3.507. The half life of 115mCd in the blood was calculated to be 158.4 days. On the 14th day after injection of 115mCdCl2 solution, 99.1% of the radioactivity in the whole blood was in the red cells, over 90% of the radioactivity in the red cells existing in the supernatant of stroma-free hemolysate. From the results of gel-filtration, DEAE Sephadex column chromatography and gel-electrophoresis, it was elucidated that about 70% of the radioactivity of the stroma-free hemolysate was bound to thionein. But the ratio of the two components in metallothionein was different between the red cells and the liver. It was also made clear that incorporation of metallothionein into red cells through cell membrane never occurred by incubating red cells with 115mCd-thionein. Considering the observations mentioned above, it was presumed that the metallothionein in the red cells may have originated from some other organ than the liver.
