1. Inter-laboratory comparison of a yeast bioassay for the determination of estrogenic activity in biological samples
- Author
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Gerrit Bor, Jennifer E. Fox, Sylvi Lehmann, Michel W. F. Nielen, Ron L.A.P. Hoogenboom, Hilda Witters, Gϋnter Vollmer, Raffaella De Maria, Ilse Becue, Karl-Werner Schramm, Toine F.H. Bovee, Silke Bernhöft, Frieda E.J. Daamen, Majorie B.M. van Duursen, Risk Assessment of Toxic and Immunomodulatory Agents, and Dep IRAS
- Subjects
green fluorescent protein ,Green Fluorescent Proteins ,RIKILT - Business Unit Veiligheid & Gezondheid ,Urine ,Tandem mass spectrometry ,Biochemistry ,Analytical Chemistry ,surface waters ,beta-agonists ,Yeasts ,medicine ,liquid-chromatography ,Animals ,Environmental Chemistry ,Bioassay ,tandem mass-spectrometry ,Sample preparation ,anabolic-steroids ,Inter-laboratory ,Spectroscopy ,BU Microbiological & Chemical Food Analysis ,validation ,Luminescent Agents ,Chromatography ,Clinical Laboratory Techniques ,Chemistry ,Organic Chemistry ,recombinant assay ,Estrogens ,Organische Chemie ,Mestranol ,Yeast ,abuse ,urine ,RIKILT - Business Unit Safety & Health ,Biological Assay ,Cattle ,BU Microbiologische & Chemische Voedselanalyse ,Gas chromatography ,medicine.drug - Abstract
An inter-laboratory exercise was performed with a yeast estrogen bioassay, based on the expression of yeast enhanced green fluorescent protein (yEGFP), for the determination of estrogenic activity in extracts of calf urine samples. Urine samples were spiked with 1 and 5 ngmL(-1) 17beta-estradiol and 17alpha-ethynylestradiol, 10 and 50 ngmL(-1) mestranol, and 100 ngmL(-1) testosterone and progesterone. Sample extracts of blank and spiked urine samples were prepared at our laboratory and sent to seven laboratories together with a reagent blank, a DMSO blank, and eight 17beta-estradiol stock solutions in DMSO ranging in concentration from 0 to 545 ngmL(-1). Sample extracts and standards were coded and tested blindly. A decision limit (CCalpha) was determined based on the response of seven blank urine samples. Signals of the negative controls, e.g. urine samples spiked with 100 ngmL(-1) testosterone or progesterone, were all below the determined CCalpha and were thus screened as compliant. Positive controls, i.e. the urine samples spiked at two levels with 17beta-estradiol, 17alpha-ethynylestradiol and mestranol, were almost all screened as suspect, i.e. gave signals above the determined CCalpha. Determined EC(50) values calculated from the 17beta-estradiol dose-response curves obtained by the seven laboratories ranged from 0.59 to 0.95 nM.
- Published
- 2009