To evaluate potential for human health effects from hormonal activity of chlorinated hydrocarbons, we will access estrogenicity, progestagenicity and androgenicity of extracted river bottom sediments that are known to be contaminated by organochlorines and other Superfund-targeted substances. A major route of human exposure is through consumption of fish which absorb these chemicals from river bottom sediments. Estrogenic and other sex-hormone like action has been postulated to account for reported associations of these compounds with reproductive dysfunction and increased rates of cancer, especially breast cancer. To date, however, most hormonal tests of environmental contaminants have focussed on their estrogenic potential. Our hypothesis is that detection of a range of hormonal and anti-hormonal activities of environmental contaminants will reflect their potential for public health risks, especially for reproductive dysfunction and cancer. Exposure may affect more than one hormone system, an outcome that could be missed by evaluating estrogenic activity alone. Hormonal activity will be determined on (1) non-polar extracts of three harbor sediments (which will be gathered and chemically characterized in Project 5) and (2) pure chemicals and mixtures of components identified in (1). Chemicals of interest are the organochlorines including pesticides (DDT and chlordane) and polychlorinated biphenyls (mixtures and individual congeners), other halogenated hydrocarbons (chlorinated ethylenes), polycyclic aromatic hydrocarbons, and plasticizers, including alkyl phenols. Heavy metals will be investigated for their potential to inhibit hormone binding. Estrogenic activity (both agonist and antagonist) will be determined using an assay developed in our laboratory that is based on estrogen- specific induction of alkaline phosphatase (AlkP) in a well- differentiated human uterine adenocarcinoma cell line (Ishikawa Var I). Progestagenicity will be tested in a similar system, also developed in our laboratory, using human breast adenocarcinoma T47D cells. An androgenicity assay will be developed using human cancer LNCaP or MFM-223 cells. Relative hormonal potencies of compounds will be determined by computation of maximal response, as well as EC50 values for agonists and IC50 values for antagonists. The applicability of the estrogen assay to environmental estrogens has already been demonstrated by its ability to measure the estrogenicity of dietary isoflavonoid phytoestrogens and kepone. The colorimetric technique is rapid, efficient and automatable; it is more expedient than other techniques based on cell proliferation that require cell counting. Our estrogen assay is as sensitive as those based on MCF7 breast cell lines. The progestagenic and androgenic assays are based on the same principle of hormone-specific induction of ALKP activity. The complement of three assays will allow rapid efficient screening of an array of chemicals and of chemical mixtures as they occur n hazardous waste sites.
Showing the most recent 10 out of 50 publications
