title: Metabolic barrier against bisphenol A in rat uterine endometrium.
abstract: Exposure to environmental chemicals with estrogenic activity during the early stage of pregnancy can seriously affect embryonic development and the maintenance of pregnancy. To estimate the metabolism and pharmacodynamics of a xenoestrogen, bisphenol A, in a reproductive organ, the metabolite of bisphenol A was analyzed after incubating a rat uterine sac in buffer solutions containing the chemical. When the inner or the outer side of the uterine sac was exposed to bisphenol A, the concentration of the parent chemical was decreased in buffer solution and then, only one metabolite, bisphenol A-glucuronide, was observed only in the outer, that is, the maternal, side. A small amount of the parent chemical could pass through the uterine sac without being modified. Uridine diphosphate (UDP)-glucuronosyltransferase (UGT) was shown by immunohistochemical staining analysis to be distributed in epithelial cells of the endometrium, oviduct, and uterine glands. Based on measurements of enzyme activity and on Western blot analysis, UGT activity toward bisphenol A and UGT protein were identified in the microsomal fractions prepared from rat uterus. UGT isoforms, such as UGT1A1, 1A2, 1A5, 1A6, and 1A7, were expressed, and MRP-1 (multidrug resistance-associated protein) and MRP-3, which are well-known to be transporters of various drug-glucuronides, were detected in the rat uterus by reverse transcription-PCR. These results elucidate the rat uterine barrier system by showing that most bisphenol A perfused into the uterus was glucuronidated in the epithelium, resulting in transport of glucuronides to the maternal side.
authors.affiliation: Department of Veterinary Biochemistry, School of Veterinary Medicine, Faculty of Environmental System, Rakuno Gakuen University, Hokkaido, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Matsumoto
authors.forename: Hidetomo
authors.initials: H
authors.lastname: Iwano
authors.forename: Hiroki
authors.initials: H
authors.lastname: Inoue
authors.forename: Naomi
authors.initials: N
authors.lastname: Iwano
authors.forename: Naoko
authors.initials: N
authors.lastname: Yamashiki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokota
mesh_terms: D000818:Animals; D001559:Benzhydryl Compounds; D001692:Biological Transport; D002851:Chromatography, High Pressure Liquid; D004717:Endometrium / Q000737:chemistry / Q000378:metabolism*; D004968:Estrogens, Non-Steroidal / Q000032:analysis / Q000493:pharmacokinetics*; D005088:Exocrine Glands / Q000201:enzymology; D005260:Female; D005965:Glucuronates / Q000032:analysis / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000378:metabolism; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D010057:Oviducts / Q000201:enzymology; D010477:Perfusion; D010636:Phenols / Q000032:analysis / Q000493:pharmacokinetics*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D004968:Estrogens, Non-Steroidal; D005965:Glucuronates; D014453:Glucuronosyltransferase; D007527:Isoenzymes; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D010636:Phenols; D012333:RNA, Messenger; C114462:multidrug resistance-associated protein 3; C006780:bisphenol A; D000098826:Bisphenol A Compounds; C421109:multidrug resistance-associated protein 1