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Zebrafish Danio rerio
and roach Rutilus rutilus: Two species suitable for
evaluating effects of endocrine disrupting chemicals?
Lene Andersen1,
Gitte I. Petersen1, Åsa
Gessbo2, Stefan Örn2,
Henrik Holbech3, Poul Bjerregaard3,
Leif Norrgren2*
1DHI
-Water and Environment, Agern Allé 11, DK-2970 Hørsholm,
Denmark
2Swedish University of Agricultural
Sciences, Faculty of Veterinary Medicine, Department of Pathology
75007 Uppsala, Sweden
3Danish Centre for Environmental
Oestrogen Research, Odense University Campnsvej 55, DK-5230
Odense M, Denmark
*Corresponding author: E-mail: LeifNorrgren
@pat.slu.se
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Abstract
Morphological studies of gonads from roach (Rutilus
rutilus) in a small Swedish lake were performed. The lake a
potential recipient for drainage water from a refuse dumping area.
All fishes were macroscopically identified as males, but histological
examination of the gonads showed a high incidence of intersex. This
high incidence might be caused by endocrine disrupting chemicals.
The relationships between exposure to endocrine disrupters and intersex
observations in wild fish is unknown and the effect of endocrine
disrupters on zebrafish (Danio rerio) were evaluated in order
to determine whether they might serve as a model laboratory species
for effects of endocrine disrupting chemicals in wild fish.
Zebrafish were exposed from pre-blastula stage until
sexual maturation to either standardised water (controls), [7a-methyltestosterone
(1, 10 µg 1-1) or 17b-estradiol
(1, 10 µg 1-1). Exposure
to both concentrations of 17b-estradiol caused a significant feminisation,
while a significant increase in the proportions of males was found
after exposure to 1 mg 17a-methyltestosterone 1-1.
Furthermore, exposure to 1 and 10 mg 17a-methyltestosterone 1-1
caused development of intersex individuals. Additionally, sexually
mature male zebrafish were exposed to 1 µg 17b-estradiol 1-1.
After 10 weeks of exposure the fish were transferred to non-contaminated
water for two weeks. lie control group was kept in standardised
water for 12 weeks. At termination of the experiment, measurement
of whole-body vitellogenin concentrations were performed. Exposure
to 17b-estradiol caused a significant increase in whole body vitellogenin
concentrations. After 2 weeks in water without addition of 17b-estradiol,
the vitellogenin concentration was reduced by approximately 50%.
Roach and zebrafish may share properties which makes these species
suitable for further comparisons to evaluate effects of endocrine
disrupting chemicals as well as domestic aid industrial effluents
containing hormone-like substances.
Keywords: intersex, vitellogenin
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