CHANGES IN THE URINARY-EXCRETION LEVEL OF 8-HYDROXYGUANINE BY EXPOSURE TO REACTIVE OXYGEN-GENERATING SUBSTANCES

A simple means of measuring of 8-hydroxyguanine (8-OHGua) levels in urine was developed. Rat and human urine samples were purified by means of strong cation exchange chromatography (Amberlite CG-120), followed by cellulose partition chromatography (Whatman CF-11). Thereafter, 8-OHGua was determined by means of high performance liquid chromatography (HPLC) using an electro-chemical detector. The level of 8-OHGua in rat urine increased by a factor of 2 to 4 after an intraperitoneal administration of 2-nitropropane (25 mg/kg), paraquat (11.3 mg/kg), or hydroquinone (11 mg/kg). On the other hand, the urine of smokers and persons exposed to air polluted with car exhaust also contained 1.9 and 3.8 fold more 8-OHGua, respectively, than that of control nonsmokers. These results indicated that the amount of 8-OHGua in urine is useful marker for monitoring the level of in vivo oxidative stress.