Vitellogenin induction in the endangered goodeid fish Girardinichthys viviparus: Vitellogenin characterization and estrogenic effects of polychlorinated biphenyls

Vitellogenin (VTG) is a widely used biomarker in studies of endocrine disruption induced by xenobiotics such as polychlorinated biphenyls (PCBs). This study evaluates the estrogenic effects of these compounds on the black-fin goodeid Girardinichthys viviparus, an endangered fish species in Mexico with a reduced range of distribution due to pollution of its natural environment. Adult fish born in the laboratory were exposed to half the LC₀ of Inerteen® commercial PCB mixture. VTG was determined through an inhibition enzyme-linked immunosorbent assay (ELISA) using a homologous-heterologous system. Male and female fish were killed after 1, 2, 4, 8 and 16 days of exposure. The distal third of each specimen was used for analysis. VTG was obtained from cultured hepatocytes and blood serum of males previously exposed to 17β-estradiol. VTG molecular mass was 348 kDa. PCBs were found to elicit greater estrogenic effects on VTG induction in males than in females (p < 0.05) and sex differences were noted. Time-dependent VTG induction kinetics in males and a stationary phase in females were also observed.