An ELISA for brown trout (Salmo trutta) vitellogenin and its use in bioassays for environmental estrogens

An enzyme linked immunosorbent assay (ELISA) was developed for the detectio n of the egg yolk precursor vitellogenin (Vg) in plasma of brown trout (Sal mo trutta). Purified Vg from a 17 beta-estradiol-induced trout was used as the competing antigen in the ELISA which is based on polyclonal antibodies. The ELISA's performance was optimized and characterized. The assay's worki ng range was (25-500 ng ml(-1)), its sensitivity was (10.5 ng ml(-1)), and it had an intra-assay coefficient of variation of less than 10% between 30 and 1000 ng ml(-1). The ELISA was used in bioassays for the detection of en vironmental estrogens, including estrogen mimics, in whole and fractionated industrial waste waters. Those bioassays were based on intraperitoneal (i. p.) injection-, static renewal-, and flow through exposure systems. The res ponse threshold of both bioassays is limited to 1-2 mu g ml(-1) Vg by a low level plasma interference that was regularly detected in plasma from non-i nduced male fish. The responsiveness of the bioassays was characterized usi ng progressive doses of 17 beta-estradiol. The i.p.-based assay, which was responsive to at least 100 mu g kg(-1) of 17 beta-estradiol, was used to sc reen extracts of pulp mill effluent and black liquor for estrogenic effects . Neither extract induced Vg in our assay. The i.p. assay was also used to test 4-tert-octylphenol (OP) and the PAH derivative, retene, for estrogenic activity. OP induced Vg in the i.p.-exposed fish; no Vg induction was dete cted in the retene-exposed fish. The static renewal bioassay, which was res ponsive to at least 0.1 mu g ml(-1) of 17 beta-estradiol over a 15-day expo sure period, was used to screen whole pulp mill effluents for estrogenic ef fects. No Vg induction was detected in the effluent-treated fish. (C) 1999 Elsevier Science B.V. All rights reserved.