| Research Abstract |
Polyhalogenated aromatic hydrocarbons (PHAHs) which include ychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) are environmental contaminants found in emissions resulting from combustion of fossil fuels; incineration of municipal, hazardous, and hospital wastes; and production of bleached paper. Human exposure to these compounds usually involves complex mixtures in the diet, particularly milk and other dairy products, fish and meat. These compounds elicit a variety of biological and toxic responses; induction of xenobiotics metabolizing enzymes, behavioral abnormalities, teratogenicity, immunotoxicity, thymus atrophy, reproductive disorders, epithelial disorders, wasting syndrome, hepato-toxicity and cancer. PHAHs tend to accumulate in liver and adipose tissue because of its high lipophilicity. In experimental animals, fecal excretion is the major route of excretion of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which is the prototype and the most potent isomer of the PHAHs, following intratracheal instillation, oral gavage, intraperitoneal or intravenous administration. Although TCDD is so hardly metabolized that tend to remain in the body for a long time, previous studies have provided evidences that TCDD is metabolized both in vivo and in vitro to more polarmetabolites. However, in mammals, it remains unclear how to metabolite TCDD and excrete its polarmetabolites in urine. Here we used 3H-TCDD to search for metabolites in urine of mice.
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