Nonmonotonic responses to low doses of xenoestrogens: A review

- Xenoestrogens are globally ubiquitous, and can directly or indirectly harm people and animals in different ways.
- The adverse effects of xenoestrogens show oscillating temporal patterns.
- The adverse effects of low-dose xenoestrogens exposure may be underestimated.
- Different xenoestrogens, doses and exposure times may yield different or even opposite responses.
- The low-dose and nonmonotonic responses to xenoestrogens are complex and time-consuming to explore, even for a specific, single substance.

Xenoestrogens (XEs) mimic or block the synthesis, metabolism and transport of normal endogenous hormones, disturbing normal endocrine function. The available data on the nonmonotonic estrogenic effects of low doses of many XEs are reviewed, covering in vitro, in vivo and epidemiological studies. The observed nonmonotonic patterns of the dose-response curves are discussed, along with possible underlying mechanisms. This review is intended to provide guidance for harm predication and to suggest prevention measures.