A chronic exposure to bisphenol A reduces sperm quality in goldfish associated with increases in kiss2, gpr54, and gnrh3 mRNA and circulatory LH levels at environmentally relevant concentrations

The bisphenol A (BPA)-disrupted reproductive functions have been demonstrated in male animals. In fish, it has been shown that environmentally relevant concentrations of BPA decrease sperm quality associated with inhibition of androgen biosynthesis. However, BPA effects on neuroendocrine regulation of reproduction to affect testicular functions are largely unknown. In the present study, reproductive functions of hypothalamus and pituitary were studied in mature male goldfish exposed to nominal 0.2, 2.0 and 20.0 μg/L BPA. At 90 d of exposure, sperm volume, velocity, and density and motility were decreased in goldfish exposed to 0.2, 2.0, and 20.0 μg/L BPA, respectively (p < 0.05). At 30 d of exposure, there were no significant changes in circulatory LH levels and mRNA transcripts of kiss1, Kiss2, gpr54, and gnrh3. At 90 d of exposure, circulatory LH levels showed trends toward increases in BPA exposed goldfish, which was significant in those exposed to 2.0 μg/L (P < 0.05). At this time, Kiss2, gpr54, and gnrh3 mRNA levels were increased in goldfish exposed to any concentrations of BPA (p < 0.05). This study shows that BPA-diminished sperm quality was accompanied by an increase in circulatory LH levels associated with increases in mRNA transcripts of upstream neuroendocrine regulators of reproduction in goldfish. Further, this is the first study to report circulatory levels of LH in fish exposed to BPA.