Evaluation of the oestrogen-receptor activating potency of environmental samples by means of yeast oestrogen assays.

A bioassay based on genetically modified yeast strains was applied to screen environmental samples for their oestrogen-like activity. The yeast system was selected from the vast number of "oestrogen bioassays" available because it permits rapid and easy handling at low costs. The test protocol developed allowed the examination of dimethyl sulfoxide-dissolved samples within one day, with an EC50 between 1.5 nM and 3.5 nM 17 beta-oestradiol and a detection limit between 0.3 nM and 0.5 nM 17 beta-oestradiol for yeast strain I. Advantages and disadvantages as well as future prospects of this kind of oestrogen bioassay will be considered by discussing selected results.