Excretion characteristics of urinary 8-hydroxydeoxyguanosine after dietary exposure to polycyclic aromatic hydrocarbons.

Urinary 8-hydroxydeoxyguanosine (8-OHdG) is considered a noninvasive marker for oxidative stress and also a marker of carcinogenic potential for compounds such as polycyclic aromatic hydrocarbons (PAHs). Although human studies have investigated urinary 8-OHdG concentrations in PAH-exposed workers and the general population, the background level and excretion kinetics of urinary 8-OHdG in humans remain unclear. Two feeding experiments (consumption of barbecued meat of 15 and 30 g/kg for Experiments 1 and 2, respectively) were conducted to examine the excretion characteristics of urinary 8-OHdG. All urine voided over 7 days was collected, but only first morning (approximately 8 A.M.) and last afternoon (approximately 5 P.M.) samples were analyzed for 8-OHdG. Mean background urinary 8-OHdG concentration was 4.76 microg/g creatinine. Statistically significant increases (P < 0.05) in urinary 8-OHdG concentration were observed on the afternoon of the 3rd and 2nd days after barbecued meat consumption for Experiments 1 and 2, respectively. A pattern of diurnal fluctuation (P < 0.05) in 8-OHdG excretion rate was evident, in that the excretion of 8-OHdG was faster during the night than during the day. Additionally, significant (P < 0.05) and strong (r > 0.6) correlations were found between urinary 8-OHdG measured 2-3 days after exposure to barbecued meat, and 1-hydroxypyrene (1-OHP) and 3-hydroxy-benzo[a]pyrene (3-OHBaP) concentrations measured within a half day after such exposure. The current results demonstrate a lag in excretion of urinary 8-OHdG relative to 1-OHP and 3-PHBaP after dietary PAH exposure. These relationships highlight the importance of sampling time when assessing PAH-related DNA lesions through urinary 8-OHdG. Copyright 2009 Wiley-Liss, Inc.