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Reproductive stimulation by low doses of xenoestrogens contrasts with the view of hormesis as an adaptive responseDepartment of Ecology and Evolution-Ecotoxicology, Johann Wolfgang Goethe University, Siesmayerstrasse 70, D-60323 Frankfurt am Main, Germany weltje{at}zoology.uni-frankfurt.de
Division of Biological Sciences, University of Missouri, Columbia, MO, USA
Department of Ecology and Evolution-Ecotoxicology, Johann Wolfgang Goethe University, Frankfurt am Main, Germany We discuss the similarities and differences of two types of effects that occur at low but not high doses of chemicals: hormesis and stimulation by oestrogenic endocrine-disrupting chemicals or xenoestrogens. While hormesis is a general phenomenon evoked by many compounds, oestrogenic stimulation occurs for specific chemicals that disrupt actions of endogenous oestrogen. Both types of phenomena can induce an inverted-U dose-response curve, from low-dose stimulation of response, and thus challenge current methods of risk assessment. Hormesis is generally thought to be caused by an over-reaction of detoxification mechanisms, which is considered an adaptive response that should protect an organism from subsequent stress. One view of the hormetic low-dose stimulatory response, i.e., increased performance, is that it is beneficial. In contrast, we propose that for manmade xenoestrogens this is never the case. This is demonstrated with examples for low doses of the oestrogenic environmental chemicals bisphenol A and octylphenol, and the oestrogenic drug-response curves is underestimated by the current threshold model used in risk assessment, and this is likely to apply to other endocrine-disrupting chemicals.
Key Words: bisphenol A • dynamic energy budget • endocrine disruption • hormesis • inverted-U • xenoestrogen
Human & Experimental Toxicology, Vol. 24, No. 9,
431-437 (2005) This article has been cited by other articles:
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