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INCORPORATION OF 5-IODO-2'-DEOXYURIDINE AND 5-BROMO-2'DEOXYURIDINE INTO RODENT DNA AS DETERMINED BY NEUTRON ACTIVATION ANALYSIS
Citation:
Kitchin, K. AND J. Brown. INCORPORATION OF 5-IODO-2'-DEOXYURIDINE AND 5-BROMO-2'DEOXYURIDINE INTO RODENT DNA AS DETERMINED BY NEUTRON ACTIVATION ANALYSIS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/563.
Description:
Using 5-iodo-2'-deoxyuridine (IdU) and 5-bromo-2'-deoxyuridine (BrdU) an DNA precursors, neutron activation analysis (NAA) of iodine and Br was developed as a quantitative method for determining DNA synthesis. ndogenous tissue concentrations of bromine (Br) and iodine ranged from a low of 0.06 ug of iodine/g of rat gastrointestinal tract (GIT) to a high of 5.99 ug of Er/g of rat kidney. ll ten rodent tissues had 3 to 75 times higher concentrations of Br than iodine. at hepatic Br concentrations could be reduced 18-fold by dietary and pharmacological methods. emale Fischer 344 rats and male C57BL/6 mice were given 4-8 intraperitoneal injections of either IdU or BrdU as a DNA precursor. issue clearance of iodine in rodents treated with IdU was both more complete and fast (4 hours or less) than Br clearance from BrdU-treated rodents (at 162 hours nonincorporated Br label still remaining. n rat liver, lung and kidney, the iodine label incorporated into DNA was stable for at least 162 hours. or IdU studies, the incorporation ratio is defined as the ug iodine/g tissue in IdU-treated rats divided by the ug iodine/g tissue-of untreated rats. AA-based studies of DNA synthesis gave high incorporation ratios in rat liver (5.3), rat lung (6.7), rat GIT (19.0), rat spleen (24.0), mouse GIT (10.1) and mouse spleen (25.8).