Induction of vitellogenin synthesis in an Atlantic salmon (Salmo salar) hepatocyte culture:: a sensitive in vitro bioassay for the oestrogenic and anti-oestrogenic activity of chemicals

A variety of organic compounds have been documented to bind to the oestrogen receptor and induce oestrogenic effects in different vertebrates. The presence of these environmental oestrogens or oestrogen mimics in the aquatic environment has been suspected of disrupting the normal endocrinology of wild populations of fish. In this study, induction of vitellogenin synthesis in primary hepatocytes from Atlantic salmon ( Salmo salar) was optimized and validated as an oestrogenic in vitro bioassay using a sensitive capture vitellogenin enzyme-linked immunosorbent assay. After proper optimization ( cell media supplements, cell density, temperature and exposure time), this assay gave a sensitive and reproducible response to both endogenous steroids ( relative potency: 17beta-oestradiol >> oestriol > oestrone > 17alpha-oestradiol) and a range of common oestrogen mimics ( relative potency: ethynyloestradiol and diethylstilboestrol >> genistein and zearalenone >> bisphenol A and 4-t-octylphenol > 4-n-nonylphenol and 2'-chloro, 4-chlorodiphenyltrichloroethane (o, p'-DDT). However, the androgen testosterone and the putative oestrogen mimics dieldrin and toxaphene were not shown to be oestrogenic using this hepatocyte bioassay. Oestrogen-induced vitellogenin synthesis was efficiently inhibited by the anti-oestrogen ZM 189.154, suggesting that this bioassay may be used for testing both the oestrogenic and the anti-oestrogenic properties of chemicals.