Effects of the fungicide prochloraz on the sexual development of zebrafish (Danio rerio)

Some chemicals have the potential to adversely affect sexual development through multiple endocrine actions. Prochloraz is an imidazole fungicide that displays diverse mechanisms of action, including inhibition of aromatase activity, inhibition of androgen synthesis, and antagonism of the androgen receptor. The objective of this study was to assess the effects of prochloraz on the sexual development of zebrafish (Danio rerio) in the Fish Sexual Development Test (FSDT) proposed as an OECD test guideline for detection of endocrine disruptors. Zebrafish were exposed to prochloraz (0, 16, 64 or 202 microg/L) for 60 days from 24 h post fertilization. Fish exposed to 202 microg/L prochloraz showed an increased proportion of males. Furthermore, the incidence of intersex and the stages of the gonads were altered in the treated fish compared to the control fish. A significant vitellogenin decrease was observed in both female and male zebrafish at an exposure concentration of 202 microg/L prochloraz. However, in the male fish, significantly increased vitellogenin concentrations were observed in the groups exposed to 16 or 64 microg/L prochloraz. This study serves as a part of the validation of the FSDT and indicates that the FSDT is suitable in detecting compounds with multiple endocrine actions. This is of importance in the assessment of the potential risk of existing and new chemicals.