Effect of Azo Dyes on Proliferation in Mouse Embryo Culture Cells

Amaranth (Food Red No. 2) and Ponceau 3R stimulate in vitro RNA synthesis by causing the dissociation of chromatin in isolated rat-liver nuclei. The effects of these azo dyes and Sunset Yellow FCF (Food Yellow No. 5) on proliferation of mouse embryo culture cells, C3H10 T1/2, were studied. 1) When the cells were pretreated for 1 hr with S9-untreated azo dyes at concentrations of 0.3. 1.0, and 5 mM, the cell growth was slightly reduced by 5 mM Ponceau 3R. All the S9 -untreated azo dyes inhibited cell growth when added to the medium during cultivation. 2) The 1-hr pretreatment of the cells with S9-treated amaranth and Ponceau 3R at a concentration of 0.3 mM temporarily accelerated the cell growth in the early stage of cell proliferation. However, this was not observed when these S9-treated azo dyes were added to the medium during cultivation.