Induction of vitellogenin and gonadal impairment in chub (Leuciscus cephalus L.) after exposure to 17beta-estradiol and testosterone.

OBJECTIVES: A controlled laboratory study was carried out to quantify vitellogenin (VTG) concentrations in a common cyprinid freshwater fish, the chub (Leuciscus cephalus L.), exposed to steroid hormones.

DESIGN: The effect of 17betaestradiol, testosterone and testosterone-estradiol mixture was investigated on vitellogenin induction. Gonad status was also determined.

RESULTS: Oral exposure to estradiol and a testosterone-estradiol mixture increased (p < 0.01) blood plasma concentrations of VTG in blood plasma of both sexes. The testosterone-estradiol mixture had a negative effect on the investigated chub gonads. The effects were signified by histological changes when compared to control fish.

CONCLUSION: Our results showed a significant VTG increase in blood plasma of both sexes, indicating that vitellogenic response in the chub is sensitive to steroid hormones.

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