Endocrine disrupting effects of benzotriazole in rare minnow (Gobiocypris rarus) in a sex-dependent manner

Benzotriazole (BT), an anticorrosive agent, is widely used in industrial applications and household dishwashing agents. Despite its reported toxicity to aquatic organisms, little is known about its endocrine disrupting effects. In this study, adult Chinese rare minnows (Gobiocypris rarus) were exposed to 0.05, 0.5, and 5 mg L−1 BT for 28 d. The pathological damage in liver was associated with hypertrophy of the hepatocytes, nuclei pyknosis and vacuolization at 5 mg L−1 groups. Additionally, the degeneration of the ovary and the stimulation of spermatogenesis were observed at 5 mg L−1 groups. The plasma 17β-estradiol level was significantly increased in the males but decreased in the females at 5 mg L−1 (p < 0.05). In the brain, the up-regulation of CYP19B, GnRHs, and LHβ mRNA was detected across all doses (p < 0.05). In the gonad, the transcriptional levels of StAR, CYP11A, 3βHSD, CYP17, 17βHSD, and CYP19A were generally decreased in the males at 5 mg L−1 (p < 0.05), whereas these genes, except for 3βHSD, were significantly increased in females at all concentrations (p < 0.05). Moreover, the expression level of VTG in the livers from all exposure groups was significantly increased compared with controls (p < 0.05). Taken together, our results indicate that BT could adversely affect the rare minnows in a sex-dependent manner.