Developmental Exposure to Anthracenen and Estradiol Alters Reproductive Success in Medaka (Oryzias latipes)

摘要

Polyaromatic hydrocarbons (PARs) impair fish reproduction and appear to antagonize estradiol action in vitra and in viva. To test the hypothesis that exposure to PARs could alter reproductive success by disrupting the effect of estrogen on sex differentiation and puberty, we exposed medaka (Oryzias tatipes) for 2 or 8 weeks post-hatch to 0, 12, and 20 .ug/L anthracene (ANT) :t 0.27 .ug/L estradiol-17{3 (E2). At the end of the exposure, fish were transferred to clean water, grown to sexual maturity (14 weeks), and separated into mating pairs. Eggs were collected, counted, and scored for % fertilization (mating success). Eight-week exposure to E2 resulted in 100% females, while the 2-week exposure resulted in 83% females and 8% feminized males. Exposure to 20.ug/L ANT for 8 weeks reduced mating success by half, but co-exposure to E2 prevented the effect. Exposure to ANT for 2 weeks did not alter mating success, but reduced the proportion of E2-induced sex reversal in co-exposed fish. Exposure to ANT did not prevent the E2 effect in fish co- exposed for 8 weeks. ANT also had a transgenerational effect on reproductive success, reducing fertility in the offspring of treated males and females. We conclude that ANT disrupts estrogen action, since anthracene-induced effects on mating success are prevented by exposure to E2, while E2-induced effects on sex ratio are prevented by exposure to anthracene.