title: Differential modulation of neuro- and interrenal steroidogenesis of juvenile salmon by the organophosphates - tris(2-butoxyethyl)- and tris(2-cloroethyl) phosphate.
abstract: Following the ban of polybrominated diphenyl ether (PBDEs) flame retardants under well-documented toxicity issues, organophosphate such as tris(2-butoxyethyl) phosphate (TBOEP) and tris(2-cloroethyl) phosphate (TCEP) were considered as potential substitutes. Although TBOEP and TCEP are consistently detected in the aquatic environment, there are few data about the possible toxicological effects of these compounds on aquatic organisms, including fish. In the present study, we have investigated the influence of TBOEP and TCEP on neuro- and interrenal steroidogenesis of juvenile Atlantic salmon (Salmo salar), after a seven-day exposure to four different concentrations (0 (control), 0.04, 0.2 and 1mg/L) of each compound. TBOEP and TCEP were diluted in Milli-Q water. The expression of genes involved in steroidogenesis (StAR, cyp19a, cyp19b, cholesterol side-chain cleavage enzyme (P450scc), 3β-hydroxysteroid dehydrogenase (3β-hsd), and 11β-hydroxylase (cyp11β)), were analyzed in the brain and head kidney using real-time PCR. Plasma 11-ketotestosterone (11-KT) analysis was performed using enzyme immunoassay (EIA). Our results showed that TBOEP accumulated more rapidly than TCEP in fish muscle tissue. Surprisingly, TBOEP produced less pronounced effects than TCEP on neural and interrenal steroidogenic responses, despite the observed rapid uptake and bioaccumulation pattern. Specifically, TBOEP produced significant and consistent concentration-specific alterations on neural- and interrenal steroidogenesis. Plasma levels of 11-KT were not significantly altered by any of the exposures. The increased expression of steroidogenic genes demonstrated in the present study could produce time-specific alterations in the production of glucocorticoids and steroid hormones that play integral roles in fish metabolism, stress responses and adaptation, sexual maturation, reproduction and migration with overt consequences on reproductive success and survival.
authors.affiliation: Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway. Electronic address: arukwe@bio.ntnu.no.
authors.forename: Augustine
authors.initials: A
authors.lastname: Arukwe
authors.affiliation: Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
authors.forename: Camilla Catarci
authors.initials: CC
authors.lastname: Carteny
authors.affiliation: Helmholtz-Center for Environmental Research - UFZ, Department of Analytical Chemistry, Permoserstr.15, 04318 Leipzig, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Möder
authors.affiliation: Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
authors.forename: Alberto
authors.initials: A
authors.lastname: Bonini
authors.affiliation: Department of Biology, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
authors.forename: Morten Andre
authors.initials: MA
authors.lastname: Maubach
authors.affiliation: Norwegian Institute of Bioeconomy Research (NIBIO), Postveien 213, N-4353 Klepp st., Norway.
authors.forename: Trine
authors.initials: T
authors.lastname: Eggen
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D029941:Fish Proteins / Q000235:genetics; D005411:Flame Retardants; D005786:Gene Expression Regulation / Q000187:drug effects; D060226:Head Kidney / Q000187:drug effects* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics; D009132:Muscles / Q000378:metabolism; D010755:Organophosphates / Q000493:pharmacokinetics / Q000633:toxicity*; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics / Q000633:toxicity*; D012474:Salmon / Q000378:metabolism; D013739:Testosterone / Q000031:analogs & derivatives / Q000097:blood; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D029941:Fish Proteins; D005411:Flame Retardants; D008565:Membrane Proteins; D010755:Organophosphates; D009943:Organophosphorus Compounds; D014874:Water Pollutants, Chemical; C031324:tris(chloroethyl)phosphate; D013739:Testosterone; D003577:Cytochrome P-450 Enzyme System; C003600:11-ketotestosterone; C013320:tris(2-butoxyethyl) phosphate
keywords: Endocrine disruptor; Fish; OPFRs; Steroidogenesis; TBOEP; TCEP