کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4471082 | 1314481 | 2006 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: No-threshold dose–response curves for nongenotoxic chemicals: Findings and applications for risk assessment No-threshold dose–response curves for nongenotoxic chemicals: Findings and applications for risk assessment](/preview/png/4471082.png)
We tested the hypothesis that no threshold exists when estradiol acts through the same mechanism as an active endogenous estrogen. A Michaelis–Menten (MM) equation accounting for response saturation, background effects, and endogenous estrogen level fit a turtle sex-reversal data set with no threshold and estimated the endogenous dose. Additionally, 31 diverse literature dose–response data sets were analyzed by adding a term for nonhormonal background; good fits were obtained but endogenous dose estimations were not significant due to low resolving power. No thresholds were observed. Data sets were plotted using a normalized MM equation; all 178 data points were accommodated on a single graph. Response rates from ∼1% to >95% were well fit. The findings contradict the threshold assumption and low-dose safety. Calculating risk and assuming additivity of effects from multiple chemicals acting through the same mechanism rather than assuming a safe dose for nonthresholded curves is appropriate.
Journal: Environmental Research - Volume 100, Issue 1, January 2006, Pages 93–99