title: Effects of benzo[a]pyrene on whole cytochrome P450-involved molecular responses in the marine medaka Oryzias melastigma.
abstract: Despite being a strong toxicant for aquatic ecosystems, the effect of benzo[a]pyrene (B[a]P) on whole cytochrome P450 (CYP) biotransformation mechanisms has not been deeply investigated in aquatic organisms. To understand the mode of action of B[a]P on CYP molecular responses in fish, we analyzed the full spectrum of cyp genes and the activities of enzymes that are involved in detoxification and antioxidant defense systems after exposure to different concentrations of B[a]P over different time courses in the marine medaka, Oryzias melastigma. Upon B[a]P exposure, we found significant downregulation of cyp genes associated with steroidogenesis with decreased concentrations of actual hormones including estradiol (E2) and testosterone (11-KT), indicating that B[a]P-treated groups were closely associated with the dysfunction of hormone synthesis in a dose-dependent manner. In addition, B[a]P exposure strongly influenced transcriptional levels of antioxidant-related genes and their enzyme activities. Based on these results, we suggest that B[a]P induced the CYPs-involved systematic biotransformation mechanism with oxidative stress in the juvenile marine medaka, resulting in changes of endogenous hormonal levels and transcriptional levels of several steroidogenic metabolism-related CYPs.
authors.affiliation: Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746, South Korea.
authors.forename: Bo-Mi
authors.initials: BM
authors.lastname: Kim
authors.affiliation: Department of Marine Science, College of Natural Sciences, Incheon National University, Incheon 406-772, South Korea.
authors.forename: Jae-Sung
authors.initials: JS
authors.lastname: Rhee
authors.affiliation: Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Chang-Bum
authors.initials: CB
authors.lastname: Jeong
authors.affiliation: Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Su-Jae
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Yong Sung
authors.initials: YS
authors.lastname: Lee
authors.affiliation: National Instrumentation Center for Environmental Management, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, South Korea. Electronic address: choii@snu.ac.kr.
authors.forename: Ik-Young
authors.initials: IY
authors.lastname: Choi
authors.affiliation: Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 440-746, South Korea. Electronic address: jslee2@skku.edu.
authors.forename: Jae-Seong
authors.initials: JS
authors.lastname: Lee
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene / Q000633:toxicity*; D001711:Biotransformation / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006728:Hormones / Q000097:blood / Q000235:genetics; D009990:Oryzias / Q000235:genetics / Q000502:physiology*; D018384:Oxidative Stress / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D006728:Hormones; D014874:Water Pollutants, Chemical; D001564:Benzo(a)pyrene; D003577:Cytochrome P-450 Enzyme System
keywords: Benzo[a]pyrene; Cytochrome P450; Detoxification; Marine medaka; Metabolism; Oryzias melastigma