Duk-Hee Lee

Publications (2)22.99 Total impact

• Article: Regulatory Decisions on Endocrine Disrupting Chemicals Should be Based on the Principles of Endocrinology.

  Laura N Vandenberg, Theo Colborn, Tyrone B Hayes, Jerrold J Heindel, David R Jacobs, Duk-Hee Lee, John Peterson Myers, Toshi Shioda, Ana M Soto, Frederick S Vom Saal, Wade V Welshons, R Thomas Zoeller
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  ABSTRACT: For years, scientists from various disciplines have studied the effects of endocrine disrupting chemicals (EDCs) on the health and wellbeing of humans and wildlife. Some studies have specifically focused on the effects of low doses, i.e. those in the range that are thought to be safe for humans and/or animals. Others have focused on the existence of non-monotonic dose-response curves. These concepts challenge the way that chemical risk assessment is performed for EDCs. Continued discussions have clarified exactly what controversies and challenges remain. We address several of these issues, including why the study and regulation of EDCs should incorporate endocrine principles; what level of consensus there is for low dose effects; challenges to our understanding of non-monotonicity; and whether EDCs have been demonstrated to produce adverse effects. This discussion should result in a better understanding of these issues, and allow for additional dialogue on their impact on risk assessment.
  Reproductive Toxicology 02/2013; · 3.23 Impact Factor
• Article: Hormones and endocrine-disrupting chemicals: low-dose effects and nonmonotonic dose responses.

  Laura N Vandenberg, Theo Colborn, Tyrone B Hayes, Jerrold J Heindel, David R Jacobs, Duk-Hee Lee, Toshi Shioda, Ana M Soto, Frederick S vom Saal, Wade V Welshons, R Thomas Zoeller, John Peterson Myers
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  ABSTRACT: For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of "the dose makes the poison," because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature. We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health.
  Endocrine reviews 03/2012; 33(3):378-455. · 19.76 Impact Factor