Estrogens bioassays

Littlefield B A, Gurpide E, Markiewicz L, et al. (1990). A simple and sensitive microtiter plate estrogen bioassay based on stimulation of alkaline phosphatase in Ishikawa cells Estrogenic action of adrenal steroids. Endocrinol. 127 2757-2762. 

Bovee T F H, Helsdingen R J R, Rietjens IM C M, et al. (2004). Rapid yeast estrogen bioassays stably expressing human estrogen receptors a and P, and green fluorescent protein a comparison of different compounds with both receptor types. J. Steroid Biochem. Mol. Biol. 91 99-109. 

Bovee T F H, Heskamp H FI, Flamers A R M, et al. (2005). Validation of a rapid yeast estrogen bioassay, based on the expression of green fluorescent protein, for the screening of estrogenic activity in calf urine. Anal. Chim. Acta. 529 57-64. 

Petit F, Le Goff P, Cravedi JP, et al. 1997. Two complementary bioassays for screening the estrogenic potency of xenobiotics Recombinant yeast for trout estrogen receptor and trout hepatoc5fte cultures. J Molecular Endocrinology 19 321-335. 

Particular attention is given to the development of new mechanistic biomarker assays and bioassays that can be used as indices of the toxicity of mixtures. These biomarker assays are typically based on toxic mechanisms such as brain acetylcholinesterase inhibition, vitamin K antagonism, thyroxin antagonism, Ah-receptor-mediated toxicity, and interaction with the estrogenic receptor. They can give integrative measures of the toxicity of mixtures of compounds where the components of the mixture share the same mode of action. They can also give evidence of potentiation as well as additive toxicity. 

Through fractionating WWTW effluents and screening those fractions with cell-based bioassays responsive to estrogens, the natural steroidal estrogens Ej and... 

Legler, J., Broekhof, J.L.M., and Brouwer, A. et al. (2000). A novel in vivo bioassay for (xeno-)estrogens using transgenic zebrafish. Environmental Science and Technology 34, 4439 444. 

Vermeirssen, E.L.M., Burki, R., and Joris, C. et al. (2005). Characterization of the estrogenic-ity of Swiss midland rivers using a recombinant yeast bioassay and plasma vitellogenin concentrations in feral male brown trout. Environmental Toxicology and Chemistry 24, 2226-2233. 

Zacharewski, T. (1997). In vitro bioassays for assessing estrogenic substances. Environmental Science and Technology 31, 613-623. 

Black LJ, Goode RL (1980) Uterine bioassay of tamoxifen, trioxifene and a new estrogen antagonist (LY117018) in rats and mice. Life Sci 26(17) 1453-1458... 

An example of a TIE approach is that described by Desbrow et al. [7]. In this work, the endocrine disrupting activity detected in effluents of seven UK WWTPs by means of a yeast-based screening assay [52] was mainly attributed to the presence of estradiol, estrone, and ethynylestradiol. However, to assess the estrogenic activity different bioassays may be used, e.g., the yeast-based recombinant estrogen receptor-reporter assay (YES), the MCF-7 cell proliferation (E-screen), and the estrogen receptor-mediated chemically activated... 

Table 3 Relative estrogenic potencies as determined by different bioassays (expressed as EEF - the molar-based 17/5-estradiol equivalency factor) (adapted from [51])... 

Finally, it is interesting to note that brominated derivatives of NP included in the present study, estrogenic in the E-Screen bioassay, were proposed to be fat-soluble [30], In fact, as non-ionic surfactants, these molecules have a hydrophilic and a hydrophobic part [31]. The presence of these brominated compounds in fat tissue of humans or animals has yet to be demonstrated. However, if they do bioaccumulate in adipose tissue, as their fat solubility suggests, they may account for the xenoestrogen burden alongside organohalogenated compounds. 

Estrogenicity of LAS, SPCs and other compounds in the E-Screen bioassay... 

The development of new tests and bioassays is likely to lengthen the list of endocrine disrupters. Recent research on hormonal disruption has not only investigated estrogens and androgens as agonists and antagonists but also considered the development of the individual and the presence of compounds that interfere in other hormonal systems, such as the thyroid system. 

When using purified triolein, most samples are amenable to bioassay after di-alytic enrichment. For example, Microtox bioassay of dialysates of SPMDs shows that the SPMDs made with the purified triolein have lower acute toxicities than dialysates from SPMDs made from unpurified triolein (Johnson, 2001). Finally, examination of the dialysates using the yeast estrogen screen (YES) assay (Routledge and Sumpter, 1996) demonstrated that the purification procedure removes all background estrogenic activity (Lebo et ah, 2004). Use of triolein purified by this process expands the potential applicability of SPMD sample extracts to include numerous bioassay procedures (see Chapter 6) and GC-MS as a standard analysis technique. 

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