Simultaneous determination of five oxidative DNA lesions in human urine

A method, involving a HPLC prepurification followed by a GC/MS analysis, ha s been set up for the measurement of nucleic acid oxidation products in hum an urine. For this purpose, isotopically labeled internal standards have be en prepared and used for isotope dilution mass spectrometric detection. Usi ng this approach, four oxidized DNA bases, i.e., 5-hydroxyuracil, 5-(hydrox ymethyl)uracil, 8-oxo-7,8-dihydroadenine, and 8-oxo-7,8-dihydroguanine, tog ether with 8-oxo-7,8-dihydro-2'-deoxyguanosine have been simultaneously qua ntified in human urine samples. The levels of the oxidized nucleic acid con stituents, as expressed in picomoles per milliliter, were determined to be, in decreasing order: 8-oxo-7,8-dihydroguanine (583 +/- 376) >5-(hydroxymet hyl)uracil (121 +/- 56) > 5-hydroxyuracil (58 +/- 23) > 8-oxo-7,8-dihydro-2 '-deoxyguanosine (30 +/- 15), 8-oxo-7,8-dihydroadenine (7 +/- 4). Attempts to determine the amount of 5,6-dihydroxy-5,6-dihydrothymine, 5-hydroxycytos ine, and 2,6-diamino-4-hydroxy5-formamidopyrimidine using the above HPLC-GC /MS method were unsuccessful.