Toxic response of hamster embryo cells on exposure to mixtures of Ni2+ and benzo(a)pyrene.

Exposure of hamster embryo cells (HEC) to mixtures of benzo(a) pyrene and soluble Ni2+ neutral salts elicits additive responses in the enhanced nucleoside excretion assay. Ni2+ shows no significant excretion response until concentrations near 10 microM are reached. Addition of 0.4 micromolar benzo(a)pyrene and 30 microM, or 325 microM Ni2+ to HEC cultures results in total excretion equal to the sum of excretions induced by the individual chemicals. These observations suggest that excretion of pyrimidines may be a useful measure of biological dosimetry.