Dietary exposure to 17α-ethinylestradiol negatively affects reproduction and health parameters of zebrafish (Danio rerio).

Pollution of the aquatic ecosystem by hormone-active substances is a frequently discussed topic these days. Such substances can pass through the sewage treatment plant system and affect aquatic life. This study tested the effect of 17α-ethinylestradiol (EE2) on individual zebrafish (Danio rerio) at an environmentally relevant concentration in fish food (10 μg/kg) and at a concentration 100 times higher (1000 μg/kg). This experiment revealed significant changes in the expression of reproductive genes, an increase in vitellogenin levels and histopathological lesions in the testes after EE2 exposure. Additionally, lipid peroxidation and changes in antioxidant enzyme activities were observed at both tested concentrations, along with morphological changes and increased mortality at the higher concentration. Even the environmentally relevant concentration of EE2 poses a danger to the aquatic organisms as it changes D. rerio's reproductive and health parameters, indicating toxicity at molecular, cell, tissue, and organism levels.