Estrogen Equivalents Research Articles

Vertical Profiles of Dioxin-like and Estrogenic Activities Associated with a Sediment Core from Tokyo Bay, Japan

In vitro bioassays were used to measure dioxin-like and estrogenic activities associated with florisil fractions of extracts from a sediment core collected from Tokyo Bay, Japan. Florisil fractions 2 (F2) and 3 (F3) elicited significant dioxin-like responses in vitro. Dioxin-like activities of F2 samples were correlated with the vertical profile of PAH concentrations (R 2 = 0.85). Contribution of PAHs to Ah receptor-mediated activities in sediments was greater than those by PCDDs/DFs, PCBs, and PCNs. The dioxin-like activity of F3 samples suggests the presence of relatively polar, Ah receptor-active compounds in the Tokyo Bay sediment core. Significant estrogenic activities, which may be related to the presence of certain estrogenic PAHs, were observed for F2 samples. Estrogen equivalents (E2-EQs) calculated from the concentrations and relative potencies of known estrogenic compounds in F2 were greater than bioassay-derived E2-EQs. This suggests that complex interactions between estrogenic and antiestrogenic compounds (PAHs, PCDD/DFs, and PCNs) may have modulated the activity. F3 samples were toxic to MVLN cells; therefore, their estrogenic activities could not be estimated.

Effects of 4‐nonylphenol on fecundity and biomarkers of estrogenicity in fathead minnows (Pimephales promelas)

AbstractAultfathead minnows (Pimophales promelas) were exposed to waterborne concentrations of 4‐nonylphenol (NP) ranging from 0.05 to 3.4 μg NP/L for 42 d. Results were similar, but slightly different, for two experiments conducted during July and August, near the beginning of the breeding season, and a second experiment conducted during September and October, at the end of the breeding season, during which the adults were maintained continuously in breeding condition. Inverted U–type dose‐response relationships were observed for egg production and for concentrations of vitellogenin (Vtg) and 17β‐estradiol (E2) in blood plasma. Concentrations of plasma Vtg were significantly different between males and females, with plasma concentrations in females ranging from 20 to 110 μg Vtg/ml. Both experiments had no statistically significant, dose‐dependent effect of NP on plasma Vtg in males but significant effects of NP on Vtg concentrations in females. In the first experiment, Vtg concentration generally increased with NP concentration, whereas the second experiment showed a negative correlation. Plasma E2 concentrations in both males and females were significantly affected by NP. The concentration of total estrogen equivalents in the plasma increased 900% because of exposure to NP. Most of this increase resulted from increased plasma E2 concentrations, with only a 4% increase resulting from the estrogen agonist activity of NP. The effects of NP on adult fathead minnows seem not to result from a direct‐acting estrogen agonist mechanism but rather from changes in the endogenous concentrations of E2 through an indirect activation mechanism of action.

Occurrence of hormonally active compounds in food: a review

The present review gives an overview of the occurrence of hormones, hormone mimics, and hormone antagonists in food. The first part deals comprehensively with concentrations of the human sex steroid hormones progesterone, 17β-estradiol estrone, and testosterone in animal and vegetable food. The dietary intake of steroid hormones (10 μg/day progesterone, 0.1 μg/day estrogens, and 0.05 μg/day testosterone) is negligible compared to the human endogenous hormone synthesis. The second part addresses the phytoestrogens (isoflavones, coumestans, other bioflavonoids, lignans, phytosterols), which occur in food in much higher amounts than steroid hormones. Therefore, they can cause hormonal effects although their estrogen equivalents (relative to 17β-estradiol) are estimated to be 10–2–10–4. These effects can be beneficial or adverse, depending on the effectiveness and amount of the ingested hormone agonist, synergistic, and antagonistic effects with other dietary or endogenous hormones, interactions with other dietary compounds (e.g. fiber and fat intake), and the hormonal status of the individual. The review also summarizes the occurrence of steroid hormone precursors and of other growth-related hormones in food (corticosteroids, indole-3-carbinol, protein hormones). It ends with the presentation of residues and contaminants of fungal or anthropogenic origin (mycoestrogens, pesticides, plastic or food additives, industrial chemicals) which have also shown hormonal or hormone-blocking properties.

Detection of Estrogen- and Dioxin-like Activity in Pulp and Paper Mill Black Liquor and Effluent Using in vitro Recombinant Receptor/Reporter Gene Assays

In vitro recombinant receptor/reporter gene assays were used to examine pulp and paper mill black liquor and effluent for estrogenic, dioxin-like, and antiestrogenic activities. Using MCF-7 cells transiently transfected with a Gal4-estrogen receptor chimeric construct (Gal4-HEGO) and a Gal4-regulated luciferase reporter gene (17m5-G-Luc), it was estimated that black liquor contains 4 ±2 ppb estrogen equivalents, while negligible estrogenic activity was observed in a methanol-extracted pulp and paper mill effluent fraction (MF). A dioxin response element (DRE)-regulated luciferase reporter gene (pGudLuc1.1) transiently transfected into Hepa1c1c7 wild-type cells exhibited a dose-dependent increase in luciferase activity following treatment with 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD), black liquor, and MF. Based on the dose-response curves, black liquor and MF contain 10 ± 4 ppb and 20 ± 6 ppt TCDD equivalents, respectively. Moreover, MF exhibited significant AhR-mediated antiestrogenic activity. These results demonstrate the utility of these bioassays and suggest that the effects observed in fish exposed to pulp and paper mill effluent may be due to unidentified ER and AhR ligands not detected by conventional chemical analysis due to the lack of appropriate standards.

Induction of phytoestrogen production in Medicago sativa leaves by irrigation with sewage water

The phytoestrogenic activity of alfalfa irrigated with sewage water was determined by radioreceptor assay (RRA) and high pressure liquid chromatography (HPLC). It was found that irrigation of alfalfa fields increased the phytoestrogenic activity measured in the leaves from 10 ng estrogen equivalents (est. eqv.) to 137 ng est. eqv. g −1, which was principally due to a rise in coumestrol (<10 μg to 60 μg g −1). Similarly, when plants grown in greenhouses under controlled conditions were irrigated with sewage water, the phytoestrogenic content rose from 34 to 48 est. eqv. g −1; ( P<0.01; n = 16). Under hydroponic conditions, addition of 1 nM of estrone to the media resulted in a significant rise in phytoestrogen content in the leaves within 48 hr (from 21.2 to 34.5 est. eqv. g −1; P<0.05, n = 10). Alfalfa irrigated with sewage water may therefore have levels of coumestrol (<30 μg g −1) which can affect fertility in cattle. The agents in the sewage water responsible for increased phytoestrogen content of the alfalfa are probably the steroidal estrogens, estradiol and estrone, which are present in sewage in concentrations ranging from 10 to 300 ng l −1.