The fungicide vinclozolin (VZ) is in use globally and known to disrupt reproductive function in male. The present study tested the hypothesis that VZ disrupts testicular function in goldfish (Carassius auratus) by affecting brain-pituitary-testis axis. Goldfish were exposed to 100, 400 and 800 μg/L VZ and 5 μg/L 17β-estradiol (E2) for comparison. In VZ treated goldfish, 11-ketotesteosterone (11-KT) secretion was changed depending on dose and duration period of treatment. Following 7 days of exposure, 11-KT was decreased in goldfish exposed to 800 μg/L VZ, while it was increased in goldfish exposed to 100 μg/L VZ after 30 days of exposure. Circulating E2 level was unchanged in VZ treated goldfish, however the E2/11-KT ratio was increased in a concentration-related manner. In E2 treated goldfish, circulatory 11-KT and E2 levels were decreased and increased, respectively, which resulted in an increase in the E2/11-KT ratio. Exposure to VZ at 100 μg/L caused a significant increase in the circulatory luteinizing hormone (LH) after 30 days. In E2 treated fish circulatory LH was decreased, significantly. Transcripts of genes encoding gonadotropin-releasing hormone and androgen receptor in the brain, and those of genes encoding LH and follicle-stimulating hormone receptors, StAR, CYP17, and 3β-HSD in the testis changed in VZ-treated goldfish depending on concentration and period of treatment. mRNA of genes encoding vitellogenin and estrogen receptor in the liver and cytochrome P450 aromatase in the brain were increased in E2-treated goldfish. The results suggest that VZ-induced changes in 11-KT were due to disruption in brain-pituitary-testis axis and provide integrated characterization of VZ-related reproductive disorders in male fish.
Keywords: Cytochrome P450 aromatase; Gonadotropin-releasing hormone; Luteinizing hormone; Sex steroids; Steroidogenic enzyme genes.
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