Simultaneous HPLC analysis of 8-hydroxydeoxyguanosine and 7-methylguanine in urine from humans and rodents.

With a recently developed high-performance liquid chromatography (HPLC) method based on anion exchange chromatography, precise fraction collection, and reversed-phase chromatography, the oxidative DNA damage marker 8-hydroxydeoxyguanosine (8-OH-dG) was measured in human urine samples. The HPLC analysis was further modified to measure 8-OH-dG in rat and mouse urine samples. In addition, the urinary RNA degradation product 7-methylguanine (m7Gua) was analyzed simultaneously. The correlation coefficient (r) for the correlation between urinary creatinine and m7Gua was 0.9 for rats and 0.8 for humans and mice. Levels of 8-OH-dG in relation to urinary creatinine were compared and found to be similar for humans and rats and twice as high for mice. Urinary levels of m7Gua, as normalized to creatinine, were several-fold higher in rodents as compared with human levels, thereby correlating with the higher resting metabolic rate of rodents. The presented results show that 8-OH-dG and m7Gua can be analyzed simultaneously and reliably in urine from humans and rodents. In addition, m7Gua may be used as a reliable marker instead of creatinine for the normalization of 8-OH-dG in urine from rats and mice and also may be used in addition to normalization with creatinine in measurements of 8-OH-dG in human urine samples.