Endocrine disruptors. Issues and perspective

The increase in the number of somatic diseases and dysfunctions in the reproductive and hormonal functions of adults and children, which was noted by the WHO in 2012, raises the question of the "endocrine disrupting" action of industrial or natural chemical substances (phytohormones) with which humans are in contact via everyday consumer products, the environment, or through professional activity. Endocrine disruptors can activate or block DNA sites by binding to specific nuclear receptors for natural hormones, but also to metabolic nuclear receptors (orphan nuclear receptors), specialized in cell maintenance and detoxification. In place of hormones, they can modify the functioning of cells in the human or animal organism, leading to the appearance of hormone-dependent pathologies and cancers.

While substances such as bisphenol A, phthalates and isoflavonoids, whose chemical structure is close to that of hormones, are strongly suspected, many other products (including caffeine and heavy metals) have been implicated in these toxic manifestations. They act at very low doses, which are difficult to analyze, and follow a non-proportional pattern (U-shaped curve). This makes it extremely difficult to define the risks involved and to set up protocols to protect potentially exposed populations and workers. Numerous research programs are underway around the world to study the phenomenon of endocrine disruption, which, according to some associations, could threaten the survival of the human species. OECD and EPA testing strategies aim to characterize the dangers of endocrine disrupting potentialities of chemical substances. These tests do not explore all aspects of hormonal and metabolic regulation in organisms, which may lead to an over- or underestimation of the endocrine disruption hazard of the substances studied, and raises the question of the specificity of existing scientific protocols. This situation of uncertainty keeps human society "between caution and irrational fear", and weighs heavily on companies' industrial development strategies.

The aim of this article is to review the current state of knowledge on the issue of endocrine disruption, with regard to mechanisms of action, detection methods for endocrine disruptors, and substances suspected of being endocrine disruptors. It mentions the regulations and standards in force, and highlights the difficulties encountered by scientists and legislators in addressing this issue. Finally, it discusses the actions that industry players can take to address scientific and regulatory uncertainties, while protecting their staff, users and consumers, and the environment, from the risk of endocrine disruption.