Androgenic and Antiandrogenic Effects of Alkylphenols and Parabens Assessed Using the Reporter Gene Assay with Stably Transfected CHO-K1 Cells (AR-EcoScreen System)

Abstract

An androgen receptor (AR)-reporter gene assay for some chemicals was examined using two different types of stably transfected CHO-K1 cell lines (AR-EcoScreen cells for androgenic activity and c-luc cells for cell toxicity evaluation). One stably expresses luciferase with androgen induction. The other stably expresses it without the need for androgen induction. We studied the responsiveness of the luciferase of AR-EcoScreen to androgen agonists and androgen antagonists. The luciferase activity of AR-EcoScreen was highly induced by androgens such as 5α-dihydroxytestosterone and testosterone. Furthermore, the luciferase activity of AR-EcoScreen was very susceptible to androgen antagonists such as hydroxyflutamide and cyproproterone acetate compared with that of MDA-kb2, which stably expresses androgen and glucocorticoid-responsive luciferase and represents a tool for screening for androgenicity. We examined the AR-reporter gene assay of some chemicals containing alkylphenols and parabens using AR-EcoScreen and c-luc cells (AR-EcoScreen system). None of the tested chemicals had any androgenic activity. However, 4-t-octylphenol, 4-n-dodecylphenol, 4-n-nonylphenol, 4-n-hexylphenol, 4-n-pentylphenol, 4-noctylphenol, and 4-n-propylphenol exerted antiandrogenicity. Isobutylparaben, n-butylparaben, isopropylparaben, and n-propylparaben also had antiandrogenic activity. The level at which these parabens effects were observed is a value that is lower than the upper limit of the acceptable daily intake (ADI, 10 mg/kg/day). 4-Ethylphenol, 4-methylphenol, ethylparaben, and methylparaben had no effect on the androgen-responsive luciferase activity. We propose that the AR-EcoScreen system is suitable for a battery of titer-1 tests to identify chemicals that affect the endocrine system, and that the ADI value of total parabens may have to be lowered in Japan.

Paraben esters: review of recent studies of endocrine toxicity, absorption, esterase and human exposure, and discussion of potential human health risks

“…Certain pesticides, the fungicide vinclozolin, bisphenol A, some phthalates and triclosan can antagonize the action of androgens in assays in vitro and in animal models (Kelce and Wilson, 1997;Sohoni and Sumpter, 1998;Gee et al, 2008). It is therefore interesting that recent reports have documented the ability of several parabens to bind to human androgen receptor (Satoh et al, 2005) and an antiandrogenic activity for all parabens tested in antagonizing the action of testosterone on reporter gene expression (Satoh et al, 2005;Chen et al, 2007; see Table 3 for details). Although male reproductive abnormalities resulting in animal models from exposure to endocrine-disrupting compounds have been attributed to the oestrogenic activity of the chemicals, the relevance of antiandrogenic properties is now receiving more serious consideration (Bay et al, 2006;Sharpe, 2006;Filby et al, 2007).…”

In vitroeffect of 4-pentylphenol and 3-methyl-4-nitrophenol on murine splenic lymphocyte populations and cytokine/granzyme production

“…While the present study did not analyze for the incidence of apoptosis/necrosis among the various cell populations, this is an area under ongoing investigation in our current studies to determine if this is an important mechanism of toxicity for these phenolics. While PP has been reported to be estrogenic (Satoh et al 2005) and cause reproductive disorders in fish (Meier et al 2011), there have been no reports about the immunotoxicity of PP so far. Here, it was seen that PP reduced splenocyte viability in a concentration-related manner.…”

“…DEP contain thousands of compounds that can have hazardous effects on human health, causing a variety of diseases, including lung cancer. 4-pentylphenol (PP) derived from GEP matter (Murahashi et al 2003) has been shown to significantly affect the endocrine and reproductive systems as well as the redox status of Atlantic cod (Satoh et al 2005;Meier et al 2007). In vivo exposure to polycyclic aromatic hydrocarbons, an important class of GEP, caused inhibitory effects on T-cell proliferation (Karakaya et al 2004).…”

In Vitro Screening Assay for Detecting Aromatase Activity Using Rat Ovarian Microsomes and Estrone ELISA

“…By using this non-radioactive aromatase assay (EIA method), we tested the inhibitory effect of 45 chemicals ( Table 1) that had previously been reported to act as EDs or to have the possibility of causing such an effect, [1][2][3][4][5][6] and 6 of these chemicals inhibited the aromatase activity. Four of the 6 chemicals are synthetic red dyes that are widely used as food additives.…”