Developmental disturbances caused by polychlorinated biphenyls in zebra fish (Brachydanio rerio)

PCB congeners 60, 104, 173 and 190 and estradiol-17beta (E2) were tested on zebrafish for their effect on early embryo development. Female fish were injected with different compounds and mated with uninjected males 10 d later. Eggs were collected and kept at 28C. Injection of E2, PCB104 and PCB60 resulted in high mortalities prior to hatching and to impairment of hatching. PCB 104 and 173 and E2 led to posterior malformations and oedemas. PCB or E2 did not reduce the number of eggs obtained at spawning although females injected with PCB60 and 190 had low appetites and were apathetic whereas PCB104, PCB173 and E2 had no effect on females. Following spawning, female fish were analysed for liver oestrogen receptor (ER) induction using zebrafish ER DNA-binding-domain cDNA as probes. Increased ER MRNA levels were observed in E2 and PCB104 injected females. PCB104 treatment mimicked the effects of E2. Following hydroxylation, PCB104 had the potential to become an E2 agonist. Some effects of PCB104 were due to oestrogen-like effects on the embryos.