EFFECTS OF A HETEROGENEOUS SET OF XENOBIOTICS ON RNA-SYNTHESIS OF YEAST-CELLS

Previously the toxicity of 45 heterogeneous environmental chemicals on growth and membrane functions in Saccharomyces cerevisiae and Chinese hamster ovary (CHO) cells (Cascorbi er al., 1993) was examined. In th is study the inhibitory effects of the same set of chemicals on yeast RNA synthesis rate, measuring [2-C-14]uracil uptake during cell prolif eration are presented. The sensitivity of this test system was three t o six times higher than that of the proliferation rate assay. In addit ion, the range of the EC(20) values were similar to the range from the mammalian CHO cell proliferation test. The relatively good correlatio n with the yeast cell growth rate (r = 0.78, P = 0.0001) suggests that yeast RNA synthesis is a simple and rapid method of detecting a wide range of toxic compounds without the disadvantage of the insensitivity of the growth rate assay. (C) 1995 Academic Press, Inc.