title: Effect of UDP-glucuronic acid on the microsome-mediated binding of benzo(a)pyrene metabolites to calf thymus DNA.
abstract: The binding of benzo(a)pyrene (BP) to DNA in the presence of liver microsomal preparations from 3-methylcholanthrene-treated rats was increased 28.5% (P < 0.001) by addition of UDP-glucuronic acid to the incubation mixture at a 100 microM concentration of BP. However this increase was not observed at lower concentrations of BP. Analysis of DNA-hydrolysates by column chromatography on Sephadex LH-20 indicated that this increase was due to greater binding of benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide. The amount of bound adducts derived from 9-hydroxybenzo(a)pyrene (9-OH BP) was not significantly affected by UDP-glucuronic acid. Addition of UDP-glucuronic acid to incubation mixtures containing microsomes from untreated rat liver caused only a slight increase in total binding. These findings suggest that UDP-glucuronyl transferase may be involved in the activation of BP.
authors.affiliation: Department of Experimental Pathology, Cancer Institute, 1-37-1, Kami-Ikebukuro, Toshima-ku, Tokyo 170, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Nemoto
authors.forename: T
authors.initials: T
authors.lastname: Hirakawa
authors.forename: S
authors.initials: S
authors.lastname: Takayama
mesh_terms: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / Q000378:metabolism; D000818:Animals; D001564:Benzo(a)pyrene / Q000378:metabolism*; D001580:Benzopyrenes / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D003911:Dextrans / Q000737:chemistry / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism; D007202:Indicators and Reagents / Q000378:metabolism; D008297:Male; D008748:Methylcholanthrene; D008862:Microsomes, Liver / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014535:Uridine Diphosphate Glucuronic Acid / Q000494:pharmacology*
chemical_list: D001580:Benzopyrenes; D003911:Dextrans; D007202:Indicators and Reagents; C021337:9-hydroxybenzo(a)pyrene; D014535:Uridine Diphosphate Glucuronic Acid; D001564:Benzo(a)pyrene; D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; D008748:Methylcholanthrene; D004247:DNA; C025614:sephadex; C427203:calf thymus DNA; D014453:Glucuronosyltransferase