Premium
Effects of bifenthrin exposure on the estrogenic and dopaminergic pathways in zebrafish embryos and juveniles
Author(s) -
Bertotto Luísa Becker,
Richards Jaben,
Gan Jay,
Volz David Christopher,
Schlenk Daniel
Publication year - 2018
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.3951
Subject(s) - bifenthrin , dopaminergic , medicine , dopamine , endocrinology , dopamine transporter , vitellogenin , homovanillic acid , tyrosine hydroxylase , biology , 3,4 dihydroxyphenylacetic acid , estrogen receptor , endocrine disruptor , chemistry , receptor , hormone , biochemistry , endocrine system , cancer , pesticide , breast cancer , gene , serotonin , agronomy
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 17β‐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), ERβ1, ERβ2, luteinizing hormone β (LHβ), follicle‐stimulating hormone β (FSHβ), 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 ERβ1 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;37:236–246. © 2017 SETAC