NRP50

Endocrine Disruptors: Relevance to Humans, Animals and Ecosystems

What are endocrine disruptors?

Chemicals with endocrine activity, also termed “endocrine disruptors”, can exert a variety of detrimental effects on humans, animals or entire ecosystems. In humans, disturbances of foetal development, a decrease in fertility and the increased incidence of breast, testicular and prostate cancer have been reported. In animals, numerous studies attest to reproductive disturbances across a broad species spectrum ranging from fishes to marine and terrestrial mammals. The extinction of otters in Switzerland is attributed to these deficiencies: polychlorinated biphenyls (PCBs), which used to be a component of lubricants, impregnating agents as well as adhesives, accumulated in the food chain and caused a decrease in fertility of female otters. At the level of ecosystems, a major concern is that endocrine disruptors could be a factor in reducing biodiversity in animals.

 

Various solvents, insecticides, pesticides, combustion products, certain drugs, cosmetics and even plant products are suspected to be endocrine active. All these chemicals have in common that they are are suspected of interfering with the endocrine system of humans and animals.

 

Principally, the action of endocrine disruptors can result from two different mechanisms: some chemicals bind as a ligand to a receptor and therefore activate or block receptor-mediated endocrine effects. Receptor-independent effects of endocrine disruptors involve interference with the synthesis, metabolism or transport of hormones.

 

Endogenous hormonal effects and endocrine disrupting effects differ in the mode and intensity of their action. These differences are only partially understood. Moreover, it is known that endocrine disruptors can simultaneously interfere with different hormone systems (e.g. oestrogens and androgens). The consequence of these multiple effects on the organism is unknown.

 

Endocrine disruptors may modulate the function of endocrine systems at concentrations far lower than levels causing general toxicity. Since certain types of hormone receptors, such as the nuclear receptor superfamily, are ubiquitous in the animal kingdom, a large number of species ranging from invertebrates to humans are potentially affected.