Introduction--workshop on characterizing the effects of endocrine disruptors on human health at environmental exposure levels

Abstract

This workshop provided a forum for discussion of methods and data needed to improve risk assessments of endocrine disruptors, with special emphasis on perturbations occurring during critical stages of development and on characterizing potential health effects at environmental exposure levels. Workshop participants were asked to suggest ways to make better use of our current knowledge on endocrine signaling pathways for quantitative evaluations of potential linkages between exposure to chemicals that perturb endocrine function and adverse health effects. Reports in the scientific literature and in the media have raised concerns that certain persistent environmental chemicals may be producing adverse effects in wildlife and in humans by interfering with the endocrine system. Some of the effects include reproductive and developmental abnormalities, increases in certain hormone-related cancers (breast, prostate, testis), and declines in wildlife populations. The term endocrine disruptors is used to describe exogenous agents that act by mimicking or antagonizing natural hormones in the body that are responsible for maintaining homeostasis and controlling normal development. Because hormone receptor systems are similar in humans and animals, effects observed in wildlife species raise concern of potential human health effects. Evaluating potential low-dose effects of environmental estrogens was identified as a major research priority at the 1997 NIEHS conference "Estrogens in the Environment." The format of the present workshop, as well as the specific issues that needed to be addressed, was conceived by an organizing committee composed of K.

Estrogenic/Antiestrogenic Activities of Polycyclic Aromatic Hydrocarbons and Their Monohydroxylated Derivatives by Yeast Two-Hybrid Assay

“…13) A crude extract prepared from Sf21 insect cells infected with hERα or β recombinant virus, kindly supplied by Professor T. Nishihara, Osaka University, was used for competition binding assay. Various concentrations of a test compound and 1.25 pmol of [2,4,6, Free and bound ligands were separated by addition of an equal volume of dextran-coated charcoal. Samples were periodically mixed on ice for 5 min and centrifuged at 15000 rpm for 1 min.…”

“…cells that did not express hERα and β) bound to hER non-specifically. Thus, any decrease of bound [2,4,6, Table 2). In general, these OHPAHs bound more strongly to hERβ than to hERα, but the difference was small.…”

“…3,4) Several screening test methods have been developed to evaluate the endocrine-disrupting activities of chemicals. As for PAHs, antiestrogenic activity was observed in a yeast assay system 5) and estrogenic ac-tivity was found in MCF-7 cells.…”

Predicted No-Effect Concentration and Risk Assessment for 17-[Beta]-Estradiol in Waters of China

“…E2 also occasionally exists in some rivers (Furuichi et al 2004;Ping 2011;Zhao et al 2009), streams (Kolpin et al 2002), and coastal water ecosystems (Hashimoto et al 2005;Pojana et al 2007) at ng/L levels, and has been detected in some sediments at ng/g levels (Hashimoto et al 2005;Labadie and Hill 2007;Schlenk et al 2005;Wang et al 2011). E2 as a potent endocrinedisrupting compound, binds to organs, activates a hormone response at relatively small concentrations (Melnick 1999), and disrupts normal sex differentiation and gametogenesis (Thompson et al 2009). Multiple potential endocrine-disrupting effects of E2 have been observed in aquatic species; such effects include reduced egg production, altered sexual characteristics, and aberrant expression of mRNA for vitellogenin (Vtg), estrogen (ER), and androgen (AR) receptor isoforms .…”

Estrogenic/Antiestrogenic Activities of Quinoid Polycyclic Aromatic Hydrocarbons

“…In recent years there has been increasing interest in endocrine disruptors which may cause dysfunction of human and wildlife endocrine systems leading to cancers, reproductive system abnormalities and immune system deficiencies. 1,2) Several screening tests have been developed to evaluate the endocrine-disrupting activities of chemicals. As for PAHs, antiestrogenic activity was observed in a yeast assay system 3) and estrogenic activity was found in MCF-7 cells.…”