Validation and application of a robust yeast estrogen bioassay for the screening of estrogenic activity in animal feed

Bovee, Toine F.H.; Bor, Gerrit; Heskamp, H.H.; Hoogenboom, L.A.P.; Nielen, Michel W. F.

doi:10.1080/02652030600557163

Cited by 45 publications

(24 citation statements)

References 17 publications

(12 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similarly, the E2 equivalence (E2 EQ) of samples was generated based on the E2 dose-response curve. The EC 50 values of E2 dose-response curve were 1 nM which was in line with those reported previously (Bovee et al 2005(Bovee et al , 2006Simons et al 2011). The LOD is 0.1 ng E2 EQ g −1 dw.…”

Section: Discussionsupporting

confidence: 92%

“…AhR agonistic potentials were determined by the microethoxyresorufin-O-deethylase (EROD) bioassay based on exposure of H4IIE rat hepatoma cells (Schwirzer et al 1999). The presence of ER (ant)agonists were determined by the application of a yeast estrogen bioassay expressing a green fluorescent reporter protein upon exposure to estrogens (Bovee et al 2004(Bovee et al , 2005(Bovee et al , 2006.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays

Wang

Bovee²,

et al. 2013

Environ Sci Pollut Res

Self Cite

View full text Add to dashboard Cite

Two types of biological tests were employed for monitoring the toxicological profile of sediment cores in the Three Gorges Reservoir (TGR), China. In the present study, sediments collected in June 2010 from TGR were analyzed for estrogen receptor (ER)-and aryl hydrocarbon receptor (AhR)-mediated activities. The estrogenic activity was assessed using a rapid yeast estrogen bioassay, based on the expression of a green fluorescent reporter protein. Weak anti-estrogenic activity was detected in sediments from an area close to the dam of the reservoir, and weak estrogenic activities ranging from 0.3 to 1 ng 17β-estradiol (E2) equivalents (EQ) g −1 dry weight sediment (dw) were detected in sediments from the Wanzhou to Guojiaba areas. In the upstream areas Wanzhou and Wushan, sediments demonstrated additive effects in coadministration of 1 nM E2 in the yeast test system, while sediments from the downstream Badong and Guojiaba areas showed estrogenic activities which seemed to be more than additive (synergistic activity). There was an increasing tendency in estrogenic activity from upstream of TGR to downstream, while this tendency terminated and converted into anti-estrogenic activity in the area close to the dam. The AhR activity was detected employing rat hepatoma cell line (H4IIE). EROD activities were found homogenously distributed in sediments in TGR ranging from 200 to 311 pg 2,3,7,8-tetrachlorodibenzo-p -dioxin (TCDD) EQ g −1 dw for total AhR agonists and from 45 to 76 pg TCDD EQ g −1 dw for more persistent AhR agonists. The known AhR agonists polycyclic aromatic hydrocarbon, polychlorinated biphenyl, and PCDD/F only explained up to 8 % of the more persistent AhR agonist activity in the samples, which suggests that unidentified AhR-active compounds represented a great proportion of the TCDD EQ in sediments from TGR. These findings of estrogenic potential and dioxin-like activity in TGR sediments provide possible weight-of-evidence of potential ecotoxicological causes for the declines in fish populations which have been observed during the past decades in TGR.

show abstract

Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays

Wang

Bovee²,

et al. 2013

Environ Sci Pollut Res

Self Cite

View full text Add to dashboard Cite

show abstract

“…According to the labels, each capsule of supplement A contained 50 mg DHEA and 10 mg vitamin C in a base of rice flour, and each capsule of supplement B contained 500 mg Tribulus terrestris, 100 mg 4-androstenedione, 100 mg DHEA, 100 mg lysine and 15 mg zinc amine acid chelate. A 100-mg aliquot of each capsule was extracted according to a method described by Bovee et al [14]. In summary, sample aliquots were mixed with 4 ml methanol and 4 ml sodium acetate buffer (0.25 M, pH 4.8), sonicated for 10 min and mixed for 15 min in a head over head apparatus.…”

Section: Extraction Of Supplement Samplesmentioning

confidence: 99%

“…The latter are relatively easy to use and very robust, making them suitable for screening of samples from practice without complex sample cleanup procedures. In addition, yeast cells lack endogenous receptors and thus lack the potential cross talk from other receptor types [14]. As a result the signals obtained in the yeast androgen bioassay may be associated only with the androgenic properties of the compound or sample extract tested.…”

Section: Introductionmentioning

confidence: 99%

Evidence of the indirect hormonal activity of prohormones using liver S9 metabolic bioactivation and an androgen bioassay

Rijk¹,

Bovee²,

Groot³

et al. 2008

Anal Bioanal Chem

View full text Add to dashboard Cite

Prohormones such as dehydroepiandrosterone (DHEA) are steroid precursors that do not show hormonal activity by themselves. Abuse of these prohormones in cattle fattening is hard to prove because of strong in vivo metabolism and the difficulty to detect metabolites which are not significantly above endogenous levels. The aim of the present work was to develop an in vitro assay capable of detecting the indirect hormonal activity of prohormones that might be present in feed supplements and injection preparations. Sample extracts were incubated with a bovine liver S9 fraction in order to mimic the in vivo metabolic activation. Subsequently incubated extracts were exposed to a highly androgen-specific yeast bioassay to detect hormonal activity. Metabolic activation of DHEA, 4-androstene-3,17-dione (4-adione) and 5-androstene-3,17-diol (5-adiol) resulted in an increased androgenic activity caused by the formation of the active androgen 17β-testosterone (17β-T), as shown by ultra-performance liquid chromatography and time-of-flight mass spectrometry with accurate mass measurement. The developed in vitro system successfully mimics the hydroxysteroid dehydrogenase (HSD)-and cytochrome P450-mediated in vivo metabolic transitions, thus allowing assessment of both bioactivity and chemical identification without the use of animal experiments. Screening of unknown supplement samples claimed to contain DHEA resulted in successful bioactivation and positive screening results according to the androgen yeast biosensor.

show abstract

“…A capsule of the supplement was opened and 100 mg of the powder was extracted as described previously for feed (Bovee et al 2006). The tablet was powdered and treated in the same way.…”

Section: Yeast Estrogen and Androgen Bioassaysmentioning

confidence: 99%

Gynaecomastia linked to the intake of a herbal supplement fortified with diethylstilbestrol

Toorians

Bovee

Rooy

et al. 2010

Food Additives & Contaminants: Part A

View full text Add to dashboard Cite

This study reports the findings of a supplement marketed on the internet for prostate problems. The supplement was orally taken by a 60-year old man with divergent hormonal levels and who was surgically treated for gynaecomastia: development of abnormally large mammary glands in males. The supplement showed a strong effect in a yeast estrogen bioassay, expressing a yeast enhanced green fluorescent protein (yEGFP) upon exposure to estrogens. Using both NMR and a gradient liquid chromatographic time of flight mass spectrometric (LC/TOFMS) method, the response was shown to be caused by very high levels of diethylstilbestrol, known for causing gynaecomastia. The gynaecomastia was most probably caused by this orally taken 'natural' herbal supplement, as the patient hormonal levels also returned to normal again when stopping the use of it. This case demonstrates that physicians need to be aware of the use of supplements with illegal components that may be responsible for unwanted side-effects.

show abstract

Validation and application of a robust yeast estrogen bioassay for the screening of estrogenic activity in animal feed

Cited by 45 publications

References 17 publications

Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays

Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays

Evidence of the indirect hormonal activity of prohormones using liver S9 metabolic bioactivation and an androgen bioassay

Gynaecomastia linked to the intake of a herbal supplement fortified with diethylstilbestrol

Contact Info

Product

Resources

About