RESUMO
Low concentrations of nonylphenol (NP) in aquatic environment can induce drastic effects on the endocrine system in animals. In this study, we examined the modulatory effects of NP on reproductive and physiological parameters in juveniles of the red seabream and black rockfish following waterborne NP exposure (0, 1, 10, and 50⯵gâ¯L-1) for 60â¯days. In red seabream exposed to 50⯵gâ¯L-1 NP, plasma levels of 17ß-estradiol (E2) and 11-ketotestosterone (11-KT) were significantly lower at 30 and 60â¯days, while E2 levels were slightly higher in 10⯵gâ¯L-1-exposed individuals at day 30. Similarly, significantly lower levels of E2 and 11-KT were observed in 10 and 50⯵gâ¯L-1-exposed black rockfish at 60â¯days, whereas the E2 level was higher in 1⯵gâ¯L-1-exposed individuals at day 30. After exposure to NP, plasma and mRNA levels of vitellogenin (VTG) were significantly higher in both species at 30 and 60â¯days, similar to the inducible effects from synthetic estrogen. Plasma cortisol levels were significantly elevated by relatively higher concentrations of NP (10 and 50⯵gâ¯L-1) at 30 and 60â¯days. Finally, 60â¯days of exposure of 50⯵gâ¯L-1 NP significantly decreased the gonadosomatic index (GSI) and increased the hepatosomatic index (HSI) in both species. The results obtained from this study provide an evidence of the endocrine disrupting potential of waterborne NP on early stages of economically important marine fish. The NP-triggered endocrine modulation can induce effects on the development of reproductive and metabolic organs in fish species.