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OVERVIEW OF EXPOSURE TO DIOXIN-LIKE COMPOUNDS AND PCBS ON DEVELOPMENTAL, IMMUNOSUPPRESSIVE, AND HORMONE-RELATED EFFECTS IN MAMMALS, INCLUDING HUMANS
Citation:
BIRNBAUM, L. S. OVERVIEW OF EXPOSURE TO DIOXIN-LIKE COMPOUNDS AND PCBS ON DEVELOPMENTAL, IMMUNOSUPPRESSIVE, AND HORMONE-RELATED EFFECTS IN MAMMALS, INCLUDING HUMANS. Presented at Society of Environmental Toxicology and Chemistry (SETAC) Annual Meeting, Milwaukee, WI, November 11 - 15, 2007.
Impact/Purpose:
The multitude of responses to TCDD will be compared across species and discussed in relation to what is known about similarities and differences between dioxins and PCBs.
Description:
Exposure to TCDD and related compounds leads to a plethora of effects in multiple species, tissues and stages of development. The response spectrum ranges from simple biochemical alterations to overtly toxic responses, including lethality. Many of the effects of TCDD and related compounds are associated with relatively high doses: lethality, wasting, lymphoid and gonadal atrophy, chloracne, hepatotoxicity, adult neurotoxicity and cardiotoxicity. Developmental effects of TCDD and related dioxin-like compounds appear to be the most sensitive indicators of exposure including effects on the developing immune, nervous, cardiovascular and reproductive systems. Effects of TCDD on the immune system, learning and the developing reproductive system of multiple animal species occur at body burdens which are close to those present at the high end of the population distribution in the background human population. Biochemical effects of TCDD on cytokine expression and metabolizing enzymes occur at body burdens within a factor of ten of clearly adverse developmental responses. Functional deficits of TCDD exposure include lethality enhancement from co-exposure to low pathogenicity influenza virus and delays in puberty. Body burden appears to be the preferred dosimetric for such persistent organic pollutants. Similar responses noted in experimental animals have also been detected in mammalian wildlife, and in some cases, in human populations. The multitude of responses will be compared across species and discussed in relation to what is known about similarities and differences between dioxins and PCBs. (This abstract does not reflect Agency policy.)