The influence of a surfactant, linear alkylbenzene sulfonate, on the estrogenic response to a mixture of (xeno)estrogens in vitro and in vivo

Abstract

The influence of a surfactant, linear alkylbenzene sulfonate, on the estrogenic response to a mixture of (xeno)estrogens in vitro and in vivo. AbstractThe effect of the presence of a surfactant on the activity of a mixture of environmental estrogens was assessed. In their natural habitat, fish are subject not only to exposure to mixtures of estrogenic compounds, as has been addressed in previous publications, but also to other confounding factors (chemical, physical and biological), which may, in theory, affect their responses to such compounds. To assess the potential for such interference, the commonly occurring surfactant, linear alkylbenzene sulfonate (LAS), was applied to the yeast estrogen screen at various concentrations, independently and together with a mixture of estrogens at constant concentrations. LAS enhanced the estrogenic activity of the mixture, an effect which became less pronounced over the course of time. This information was used to design an in vivo study to assess induction of vitellogenin in fathead minnows exposed to the same mixture of estrogens plus LAS. A similar trend was observed, that is, the response was enhanced, but the effect became less pronounced as the study progressed. However, the enhanced response in vivo only occurred at the highest concentration of LAS tested (362 µg/L), and was transient because it was no longer apparent by the end of the study. Although LAS is a significant contaminant in terms of both concentration and frequency of detection in the aquatic environment, these data do not suggest that it will have a significant impact on the response of fish to environmental estrogens.

Toxic masking and synergistic modulation of the estrogenic activity of chemical mixtures in a yeast estrogen screen (YES)

“…2 and electronic supplementary material). In an independent parallel study of a different mixture of five (xeno)estrogens in the presence of LAS (alkyl chain length not specified), the same phenomenon was observed in both the original version of the YES assay and an in vivo assay detecting estrogen-dependent vitellogenin induction in fish (Harris et al 2009). In the YES, this might be the result of increased cell membrane permeability, an effect particularly well studied for structurally similar surfactants such as sodium dodecyl sulphate (SDS) (Singer and Tjerdema 1993).…”

Gene Expression of Fathead Minnows (Pimephales promelas) Exposed to Two Types of Treated Municipal Wastewater Effluents

“…It is known that chemicals with similar modes of action can be additive by targeting the same nuclear receptors . For example, exposure to low levels of individual estrogenic chemicals in a mixture can produce additive effects in fathead minnows . It is also plausible that effluent chemicals not measured in this study contributed to the responses.…”

“…53 For example, exposure to low levels of individual estrogenic chemicals in a mixture can produce additive effects in fathead minnows. 54 It is also plausible that effluent chemicals not measured in this study contributed to the responses. Effluent mixtures can be very complex; in addition to parent chemicals they may also contain metabolites that could have estrogenic activities.…”

Aromatic Naphthenic Acids in Oil Sands Process-Affected Water, Resolved by GCxGC-MS, Only Weakly Induce the Gene for Vitellogenin Production in Zebrafish (Danio rerio) Larvae

“…Interactive effects between the surfactant-like behavior and the estrogenic activity may also be possible. Harris et al 27 reported that the presence of the surfactant linear alkylbenzene sulfonate enhanced the estrogenic activity of a mixture of environmental estrogens. This effect was observed not only in a yeast estrogen screen assay but also with vtg induction in fathead minnow.…”