Nonylphenol exposure is associated with oxidative and nitrative stress in pregnant women

Animal studies have shown that exposure to nonylphenol (NP) increases oxidative/nitrative stress, but whether it does so in humans is unknown. This study examines prenatal exposure to NP and its effects on oxidatively/nitratively damaged DNA, lipid peroxidation, and the activities of antioxidants. A total of 146 urine and blood specimens were collected during gestational weeks 27-38 and hospital admission for delivery, respectively. Urinary NP was analyzed by high-performance liquid chromatography (HPLC). Urinary biomarkers of oxidatively/nitratively damaged DNA and lipid peroxidation, including 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), 8-nitroguanine (8-NO(2)Gua), 8-iso-prostaglandin F(2α) (8-isoPF(2α)) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA), were simultaneously analyzed using isotope-dilution liquid-chromatography/electron spray ionization tandem mass spectrometry. The activities of maternal plasma superoxide dismutase and glutathione peroxidase were analyzed by enzyme-linked immunosorbent assay. Urinary NP level was significantly associated with 8-oxodG and 8-NO(2)Gua levels in late pregnancy, suggesting that NP may enhance oxidatively and nitratively damaged DNA. The adjusted odds ratios for high 8-oxodG level exhibited a significantly dose-response relationship with NP levels, stratified into four quartiles. 8-oxodG appears to be a more sensitive and effective biomarker of NP exposure than 8-NO(2)Gua. These relationships suggest NP may play a role in the pregnancy complications.