Effects of 2,2′4,4′5,5′-hexachlorobiphenyl (PCB 153) on plasma sex steroids and vitellogenin in rockfish (Sebastes schlegeli)

We examined the estrogenic effect of 2,2′4,4′5,5′-hexachlorobiphenyl (PCB 153) on the rockfish, Sebastes schlegeli. We measured levels of plasma estradiol-17β (E2) and testosterone (T) by radioimmunoassay (RIA). Plasma concentrations of T and 17α-hydroxyprogesterone in female and male fish injected with PCB 153 using two dosages (0.16 mg/kg body weight. and 0.57 mg/kg) did not differ significantly between sexes or from sham-injected controls of the same sex. Plasma concentrations of E2 in females injected with PCB 153 (both levels) increased at 12 and 24 h. Concentrations of plasma vitellogenin (VTG) in females increased 72 h after injection with PCB 153 and reached 0.38 and 1.25 mg/mL, respectively. No VTG was detected in males injected with the same dosage. These results suggest that PCB 153 may lead to the production VTG in female rockfish through a synergistic effect with E2, resulting in indirect disruption of the aromatization process.