Formation of active oxygen species from diethylstilbestrol, a synthetic estrogen, and its metabolite in the presence of RAW 264.7 cells

Previously, we reported that (±)-IA but not DES produces O ₂^- spontaneously in PBS. We are interested in the possibility that these compounds might produce active oxygen species under mild cell culture conditions. On incubation of RAW 264.7 cells with (±)-IA, the signal of 5,5′-dimethyl-1-pyrroline-N-oxide (DMPO)-OH adducts increased but no more than the additive effect. However, stimulation of RAW cells with LPS and INF-γ enhanced the formation of DMPO-OH adducts slightly more than the additive effect, especially when the concentration of (±)-IA increased. In the case of DES, the spectra of DMPO-OH adducts did not increase concentration-dependently in the absence of RAW 264.7 cells, however in their presence, they increased concentration-dependently, especially when these cells were stimulated with LPS and IFN-γ. The results were interpreted to mean that DES would have a higher oxidation potential than (±)-IA, not be oxidized to semiquinoes spontaneously, and therefore not produce DMPO-OH adducts in the absence of RAW cells. In their presence, DES might be easily oxidized to semiquinones by the reaction with O₂ ^- produced from RAW 264.7 cells.