Sexual disruption in zebrafish (Danio rerio) exposed to mixtures of 17α-ethinylestradiol and 17β-trenbolone

Publication date: Available online 21 December 2015 Source:Environmental Toxicology and Pharmacology Author(s): Stefan Örn, Henrik Holbech, Leif Norrgren Environmental estrogens and androgens can be present simultaneously in aquatic environments and thereby interact to disturb multiple physiological systems in organisms. Studies on interaction effects in fish of androgenic and estrogenic chemicals are limited. Therefore, the aim of the present study was to evaluate feminization and masculinization effects in zebrafish (Danio rerio) exposed to combinations of two synthetic steroid hormones detected in environmental waters: the androgen 17β-trenbolone (Tb) and the estrogen 17α-ethinylestradiol (EE2). Juvenile zebrafish were exposed between days 20-60 post-hatch to different binary mixtures of Tb (1, 10, and 50ng/L) and EE2 (2 and 5ng/L). The endpoints studied were whole-body homogenate vitellogenin concentration at 40 days post-hatch, and sex ratio including gonad maturation at 60 days post-hatch. The feminizing potency of 5ng/L of EE2, alone as well as in combination with Tb, was clear in the present study, with exposures resulting in almost all-female populations and females being sexually immature. Masculinization effects with male-biased sex ratios were observed when fish were exposed to 2ng/L of EE2 in combination with Tb concentrations. Intersex fish were observed after exposure to mixtures of 2ng/L EE2 with 50ng/L Tb. Sexual maturity generally increased amon...
Source: Environmental Toxicology and Pharmacology - Category: Environmental Health Source Type: research