Effects of bifenthrin exposure on the estrogenic and dopaminergic pathways in zebrafish embryos and juveniles.
Environ Toxicol Chem
; 37(1): 236-246, 2018 01.
Article
em En
| MEDLINE
| ID: mdl-28815728
ABSTRACT
Bifenthrin is a pyrethroid insecticide used in urban and agricultural applications. Previous studies have shown that environmentally relevant (ng/L) concentrations of bifenthrin increased plasma concentrations of 17ß-estradiol (E2) and altered the expression of dopaminergic pathway components. The dopaminergic neurons can indirectly regulate E2 biosynthesis, suggesting that bifenthrin may disrupt the hypothalamic-pituitary-gonadal (HPG) axis. Because embryos do not have a complete HPG axis, the hypothesis that bifenthrin impairs dopamine regulation was tested in embryonic and 1-mo-old juvenile zebrafish (Danio rerio) with exposure to measured concentrations of 0.34 and 3.1 µg/L bifenthrin for 96 h. Quantitative reverse transcriptase polymerase chain reaction was used to investigate transcripts of tyrosine hydroxylase (TH), dopamine receptor 1 (DR1) and 2A (DR2A), dopamine active transporter (DAT), estrogen receptor α (ERα), ERß1, ERß2, luteinizing hormone ß (LHß), follicle-stimulating hormone ß (FSHß), vitellogenin (VTG), cytochrome P450 cyp19a1a, and cyp19a1b. Levels of E2 were measured by enzyme-linked immunosorbent assay (ELISA). Dopamine and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) concentrations were measured by liquid chromatrography-tandem mass spectrometry (LC-MS/MS). Significant decreases in TH and DR1 transcripts and HVA levels, as well as ratios of HVA/dopamine and HVA+DOPAC/dopamine, in zebrafish embryos were observed after bifenthrin treatment. In juveniles, a significant increase in the expression of ERß1 and the DOPAC to dopamine ratio was noted. These results show a possible antiestrogenic effect of bifenthrin in embryos, and estrogenicity in juveniles, indicating life-stage-dependent toxicity in developing fish. Environ Toxicol Chem 2018;37236-246. © 2017 SETAC.
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MEDLINE
Assunto principal:
Piretrinas
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Peixe-Zebra
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Dopamina
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Embrião não Mamífero
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Exposição Ambiental
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Estrogênios
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article