Comparative estrogenicity of estradiol, ethynyl estradiol and diethylstilbestrol in an in vivo, male sheepshead minnow (Cyprinodon variegatus), vitellogenin bioassay

An in vivo bioassay for vitellogenin (VTG) synthesis was developed to scree n individual chemicals or mixtures of chemicals for potentially estrogenic effects in a marine teleost model. An enzyme-linked immunosorbent assay (EL ISA) was used to quantitate VTG synthesis in male sheepshead minnows (Cypri nodon variegatus) exposed to five concentrations of the natural estrogen (1 7 beta-estradiol), a synthetic, steroidal pharmaceutical estrogen (17 alpha -ethynyl estradiol), or a synthetic, non-steroidal, pharmaceutical estrogen (diethylstilbestrol) for 16 days. At an exposure concentration of 20 ng/l, only diethystilbestrol elicited a vitellogenic response. At all test conce ntrations greater than 100 ng/l, VTG appeared in the plasma in a dose-depen dent manner for the three estrogen treatments. Liver VTG mRNA measurements were also made, exhibiting no clear correlations between quantities, nor te mporal appearance of the message and mature protein were apparent. This ass ay is short-term relatively inexpensive, shows a direct response, and easil y quantitated. (C) 2000 Elsevier Science B.V. All rights reserved.