title: Differences in metabolite burden of di(2-ethylhexyl)phthalate in pregnant and postpartum dams and their offspring in relation to drug-metabolizing enzymes in mice.
abstract: Di(2-ethylhexyl)phthalate (DEHP) induced adverse effects on mice offspring, and the metabolite mono(2-ethylhexyl)phthalate (MEHP) may be essential to determine the toxicity. In this experiment, we measured liver MEHP levels and the factors determining the metabolism, two enzyme activities [lipase and uridine 5'-diphosphate-glucuronosyltransferase (UGT)] or expression of cytochrome P450 4A14 (CYP4A14) in dams (on gestational day 18 and postnatal day 2) and their offspring. MEHP concentrations in the liver from pregnant dams were 1.5 times higher than those of postpartum dams at exposure to 0.05% DEHP. Accordingly, MEHP concentrations were 1.7 times higher in fetuses than in pups at the dose. Interestingly, lipase activity was 1.8-fold higher in pregnant dams than postpartum ones, but no such difference was noted in the activity between fetuses and pups. UGT activity was also 1.5-fold higher in pregnant dams than postpartum ones, whereas the activity in the fetuses was 1/2 that of pups. No difference was noted in CYP4A14 levels between pregnant and postpartum mice, whereas the levels in the fetuses were <1/10 those of pups. DEHP exposure did not influence lipase activity, whereas it slightly enhanced UGT activity and exclusively increased CYP4A14 levels in pregnant and/or postpartum dams. Taken together, the higher MEHP levels in pregnant dams than postpartum ones may be primarily due to higher lipase activities in pregnant dams, which may closely reflect those in fetuses and pups.
authors.affiliation: Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Tsurumai-Cho, Showa-Ku, Nagoya 466-8550, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ito
authors.forename: Yukie
authors.initials: Y
authors.lastname: Yanagiba
authors.forename: Michihiro
authors.initials: M
authors.lastname: Kamijima
authors.forename: Hisao
authors.initials: H
authors.lastname: Naito
authors.forename: Tamie
authors.initials: T
authors.lastname: Nakajima
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D000072470:Cytochrome P450 Family 4; D004051:Diethylhexyl Phthalate / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism / Q000493:pharmacokinetics* / Q000633:toxicity; D005260:Female; D005333:Fetus / Q000187:drug effects / Q000378:metabolism*; D014453:Glucuronosyltransferase / Q000378:metabolism; D008049:Lipase / Q000378:metabolism; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D010968:Plasticizers / Q000032:analysis / Q000493:pharmacokinetics* / Q000633:toxicity; D049590:Postpartum Period / Q000378:metabolism*; D011247:Pregnancy
chemical_list: C436963:Cyp4a14 protein, mouse; D010968:Plasticizers; D003577:Cytochrome P-450 Enzyme System; D004051:Diethylhexyl Phthalate; D000072470:Cytochrome P450 Family 4; D014453:Glucuronosyltransferase; D008049:Lipase; C016599:mono-(2-ethylhexyl)phthalate