title: Effects of Tributyltin and Other Retinoid Receptor Agonists in Reproductive-Related Endpoints in the Zebrafish (Danio rerio).
abstract: Both field and experimental data examined the influence of exposure to environmental contaminant tributyltin (TBT) on marine organisms. Although most attention focused on the imposex phenomenon in gastropods, adverse effects were also observed in other taxonomic groups. It has been shown that imposex induction involves modulation of retinoid signaling in gastropods. Whether TBT influences similar pathways in fish is yet to be addressed. In this study, larvae of the model teleost Danio rerio were exposed to natural retinoids, all-trans-retinoic acid, 9-cis-retinoic acid, and all-trans-retinol, as well as to the RXR synthetic pan-agonist methoprene acid (MA) and to TBT. Larvae were exposed to TBT from 5 days post fertilization (dpf) to adulthood, and reproductive capacity was assessed and correlated with mode of action. TBT significantly decreased fecundity at environmentally relevant levels at 1 μg TBT Sn/g in diet. Interestingly, in contrast to previous reports, TBT altered zebrafish sex ratio toward females, whereas MA exposure biased sex toward males. Since fecundity was significantly altered in the TBT-exposed group with up to 62% decrease, the potentially affected pathways were investigated. Significant downregulation was observed in brain mRNA levels of aromatase b (CYP19a1b) in females and peroxisome proliferator activated receptor gamma (PPARg) in both males and females, suggesting an involvement of these pathways in reproductive impairment associated with TBT.
authors.affiliation: a Interdisciplinary Centre for Marine and Environmental Research (CIIMAR), CIMAR Associate Laboratory , University of Porto Porto , Portugal.
authors.forename: Daniela
authors.initials: D
authors.lastname: Lima
authors.forename: L Filipe C
authors.initials: LF
authors.lastname: Castro
authors.forename: Inês
authors.initials: I
authors.lastname: Coelho
authors.forename: Ricardo
authors.initials: R
authors.lastname: Lacerda
authors.forename: Manuel
authors.initials: M
authors.lastname: Gesto
authors.forename: Joana
authors.initials: J
authors.lastname: Soares
authors.forename: Ana
authors.initials: A
authors.lastname: André
authors.forename: Ricardo
authors.initials: R
authors.lastname: Capela
authors.forename: Tiago
authors.initials: T
authors.lastname: Torres
authors.forename: António Paulo
authors.initials: AP
authors.lastname: Carvalho
authors.forename: Miguel M
authors.initials: MM
authors.lastname: Santos
mesh_terms: D000818:Animals; D004032:Diet; D023381:Endpoint Determination; D005260:Female; D007814:Larva; D008297:Male; D009153:Mutagens; D012098:Reproduction / Q000187:drug effects*; D047488:Retinoid X Receptors / Q000819:agonists*; D012744:Sex Ratio; D014158:Transcription, Genetic / Q000187:drug effects; D014220:Trialkyltin Compounds / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015027:Zebrafish / Q000502:physiology*
chemical_list: D009153:Mutagens; D047488:Retinoid X Receptors; D014220:Trialkyltin Compounds; D014874:Water Pollutants, Chemical; C011559:tributyltin