A large spectrum of pro-oxidant agents, including molecules with lipoperoxidative effect, can modulate gene expression through modification of the DNA binding activity of the transcription factors activator protein 1 (AP-1) and nuclear factor kappa B (NF-kappa B). In this study the effect on these redox-sensitive factors by 4-hydroxy-2-nonenal (HNE), a major aldehydic product of lipid peroxidation, was examined in two cell lines of the macrophage type. Incubation in the presence of microM concentrations of the aldehyde led to a rapid increase of AP-1 binding with a transient maximum 30 min from HNE addition to the culture medium in both cell lines VSports手机版. On the contrary, HNE did not stimulate nuclear translocation of NF-kappa B. The diverging effect of HNE on the two transcription factors is likely related to the demonstrated differential activation pathway of AP-1 and NF-kappa B in macrophages. The HNE-induced activation of AP-1 suggests the aldehyde's involvement in the regulatory mechanisms of cell proliferation and differentiation. .