Cadmium‐induced alterations in RNA metabolism in cultures of Chinese hamster cells sensitive to and resistant to the cytotoxic effects of cadmium

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Abstract
A variant population (CdR) of cultured Chinese hamster cells (line CHO) was derived that is more than 100 times as resistant to the cytotoxic effects of Cd 2+ than is the parent population. The effects on RNA metabolism of exposure to sublethal concentrations of Cd 2+ were studied in CHO and CdR. Exposure to 2X10 ‐7 M CdCI 2 for 24 h resulted in increased polysome content (1.2 times) and increased uridine or adenosine incorporation into heterogeneous nuclear RNA (1.2–1.4 times) and messenger RNA (1.5–1.7 times) in both populations. Measurement of ATP pool specific activity following exposure to radiolabeled adenosine showed that increased incorporation reflects increased synthesis. The equivalence of CHO and CdR in dose‐response in terms of stimulated RNA synthesis and their disparity in dose‐response in terms of cytotoxic effects indicate that the systems involved in conferring protection against the lethal effects of Cd 2+ are not similarly involved in attenuating the effects on RNA metabolism.