Endocrine disruption effects of p,p'-DDE on juvenile zebrafish.
The persistent organic pollutant p,p'-DDE, the major metabolite of the insecticide DDT, has displayed evidence of endocrine disruption through the inhibition of androgen binding to androgen receptors in different species. Although p,p'-DDE was continuously detected in wild fish with abnormal gonad development such as intersex, little is known about its mode of action during gonad development in fish. To elucidate the potential endocrine effects of this pollutant in zebrafish (Danio rerio), juveniles (30 days post hatch) were exposed to p,p'-DDE during the critical window of sexual differentiation. Fish were exposed to sublethal concentrations ranging from 0.01 to 20 µg l(-1) over 14 days and were maintained in control water for an additional 4 months. As core endpoints, the vitellogenin (vtg) concentration was measured at the end of exposure, and sex ratio and the gonadosomatic index were assessed 4 months after the end of exposure. An increase in vtg production in whole body homogenate was observed in fish exposed to 0.2 and 2.0 µg l(-1) p,p'-DDE. No significant differences were displayed in morphological parameters such as the gonadosomatic index of males and females or sex ratio. However, exposed females presented histopathological changes that include the reduction of the number of mature oocytes, which might impair their successful reproduction. These results demonstrate the ability of p,p'-DDE to cause endocrine disruption in zebrafish exposed during gonad differentiation of juvenile specimens. Furthermore, vtg induction by p,p'-DDE in juvenile zebrafish arises as a predictive marker for adverse effects of this DDT metabolite on the ovarian function of female zebrafish.
Department of Biology & CESAM, University of Aveiro, 3810-193, Aveiro, Portugal.
Marta Sofia
MS
Monteiro
Maria
M
Pavlaki
Augusto
A
Faustino
Alexandra
A
Rêma
Mariana
M
Franchi
Letícia
L
Gediel
Susana
S
Loureiro
Inês
I
Domingues
Jaime
J
Rendón von Osten
Amadeu
A
Mortágua Velho Maia Soares
D000818:Animals; D003633:Dichlorodiphenyl Dichloroethylene / Q000633:toxicity*; D052244:Endocrine Disruptors / Q000633:toxicity*; D005260:Female; D007928:Lethal Dose 50; D008297:Male; D010053:Ovary / Q000187:drug effects / Q000254:growth & development / Q000473:pathology; D012733:Sex Differentiation / Q000187:drug effects*; D012744:Sex Ratio; D023382:Toxicity Tests, Acute; D059551:Toxicity Tests, Subacute; D014819:Vitellogenins / Q000378:metabolism; D015027:Zebrafish / Q000254:growth & development* / Q000378:metabolism
D052244:Endocrine Disruptors; D014819:Vitellogenins; D003633:Dichlorodiphenyl Dichloroethylene
Danio rerio; antiandrogen; ecotoxicology; fish; histopathology; persistent organic pollutant; pesticide; vitellogenin