Altered Growth and RNA Metabolism in Cultured Chinese Hamster Ovary Cells Exposed to Low Levels of Cadmium July 1, 1976—June 30, 1977

摘要

This report summarizes measurements of the uptake and intracellular distribu¬tion of cadmium in cultured Chinese hamster cell3 exposed to CdCl2 at growth medium concentrations ranging from 2 ×10-7 M Cd++, which 3hows no effect on cell proliferation, to 3× 10-6 M Cd++, which stops cell division within 24 h after beginning exposure. These studies demonstrate a rapid accumulation of intracellular cadmium during the first 24 h of growth in Cd++-containing medium. During this period, cells accumulate 10 to 20 μg Cd++/g of calls, which is 500- to 1000-fold greater than the Cd++ concentration in the medium (0.02 μg Cd++/g medium). After 24 h, there is little further accumulation of Cd++ by cells. Less than 1％ of the intracellular Cd++ is found in an unbound form. Determination of subcellular distribution of Cd++ by cellular fractionation methods indicates that 80 to 90％ of the Cd++ is located in the cytoplasm and 10 to 20％ in the nucleus. The distribution of Cd++ between cytoplasm and nucleus does not change with continued growth in Cd++. Of the nuclear Cd++, approximately 70％ is bound to the chromatin fraction.