Levels of ornithine decarboxylase activation used as a simple marker of metal induced growth arrest in tissue culture

Abstract

Exposure of proliferating cells to specific water solube metal compounds at 0.1 or 1.0 mM concentrations inhibited cell growth and also depressed the induction of ornithine decarboxylase, an enzyme which is tightly coupled to the initiation of cell growth. Salts of Co ++, Ni ++, Cu ++, Cr +6 and Cd ++ significantly reduced incorporation of radiolabeled leucine, thymidine or uridine into trichloroacetic acid insoluble material, inhibited the doubling of Chinese hamster ovary cells, and blocked the the induction of ornithine decarboxylase. The addition of similar concentrations of other metals such as Fe ++, K +, Mg ++, Pb ++, Ca ++ or Sn ++ had no effect on ODC induction and also did not inhibit the other parameters associated with cell proliferation which were measured. These results suggest that ornithine decarboxylase induction can be used as a marker of metal induced growth arrest.