Probenecid, an inhibitor of transmembrane organic anion transporters, alters tissue distribution of DNA adducts in 1-hydroxymethylpyrene-treated rats.
1-Methylpyrene (1-MP), an abundant alkylated polycyclic aromatic hydrocarbon, is activated by side-chain hydroxylation to 1-hydroxymethylpyrene (1-HMP) and subsequent sulfo-conjugation to electrophilic 1-sulfooxymethylpyrene (1-SMP). In rats, this activation mainly occurs in liver. 1-SMP may react with hepatic DNA or be exported into the blood circulation to reach other tissues, in particular kidneys. Findings with recombinant cell lines suggest that renal 1-SMP uptake proceeds via organic anion transporters (OATs). Here, we tested the hypothesis that probenecid, a characteristic OAT inhibitor, interferes with kidney damage brought about by 1-SMP formed in rats. 1-HMP was administered intraperitoneally to 30 rats, half of which were co-treated with probenecid. The tissue distribution of DNA adducts was analyzed using (32)P-postlabeling and isotope dilution LC-MS/MS for the detection of the adducts N(2)-(1-methylpyrenyl)-2'-deoxyguanosine and N(6)-(1-methylpyrenyl)-2'-deoxyadenosine. In rats treated solely with 1-HMP, adduct levels in kidney tissue were about 3-fold and 8-fold higher than those in liver and lung, respectively. After co-treatment with probenecid, hepatic and pulmonary adduct levels were 12-fold and 4-fold elevated, respectively, whereas renal adduct levels were slightly lower compared to those of rats receiving 1-HMP alone. Moreover, serum levels of 1-SMP were increased 23-fold in animals pre-treated with probenecid. The differential effects on hepatic and pulmonary adduct levels suggest that not only renal OATs, but also additional anion transporters, e.g. those mediating the hepatic export of 1-SMP into the bile, were inhibited. Thus, transmembrane transport proteins play a crucial role in the distribution of reactive phase II metabolites, and thereby in tissue allocation of DNA adducts.
Monien
Bernhard H
BH
Department of Toxicology, German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany. monien@dife.de
Müller
Carolin
C
Bakhiya
Nadiya
N
Donath
Claudia
C
Frank
Heinz
H
Seidel
Albrecht
A
Glatt
Hansruedi
H
D000818:Animals; D001646:Bile / Q000378:metabolism; D002853:Chromatography, Liquid; D018736:DNA Adducts / Q000378:metabolism; D007274:Injections, Intraperitoneal; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D008297:Male; D027361:Organic Anion Transporters / Q000037:antagonists & inhibitors*; D011339:Probenecid / Q000494:pharmacology*; D011721:Pyrenes / Q000493:pharmacokinetics / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D053719:Tandem Mass Spectrometry; D014018:Tissue Distribution
D018736:DNA Adducts; D027361:Organic Anion Transporters; D011721:Pyrenes; C102088:1-sulfooxymethylpyrene; C065833:1-hydroxymethylpyrene; D011339:Probenecid