Languages:
Home » Endocrine Disruptors » Level 3 » Question 1

Endocrine Disruptors

1. What are Endocrine Disruptors (EDCs)?

  • 1.1 What is the endocrine system?
  • 1.2 What is the definition of endocrine disruptors?
  • 1.3 Why is there concern about endocrine disruptors?

1.1 What is the endocrine system?

The source document for this Digest states:

The endocrine system originally was considered to consist only of glands that secreted hormones into the blood that traveled to distant target tissues, bound to specific cellular receptors, and produced characteristic actions. Currently, our concept of "endocrine" has been broadened by the discovery of other chemical regulators, such as chemicals secreted into the blood by neurons, that are sometimes termed neurohormones. The term "cytocrine" has been applied to numerous local or intercellular chemical regulators, including growth factors. Intercellular cytocrines that travel through the extracellular fluids to other cells in a tissue also are known as paracrine and autocrine regulators, depending on whether they affect other cells or themselves, respectively. The term "intracrine" has been suggested for intracellular regulators such as second messengers and transcription factors. Even before allowing for the increase in complexity of "endocrinology" that has resulted from recent recognition of the many cytocrine/paracrine systems that operate, it had been realized that there were numerous "classica" endocrine systems in the body that regulate processes as diverse as blood pressure, smooth muscle contraction, fluid balance, and bone resorption.

Source & ©: IPCS "Global Assessment of the state-of-the-science of Endocrine disruptors "
 Endocrinology and Endocrine Toxicology (Chapter 3) page 11 section 3.2.1

For an overview of the endocrine system and its different axies such as the hypothalamic-pituitary-gonadal (HPG) axis, the hypothalamic-pituitary-adrenal (HPA) axis and the hypothalamic-pituitary-thyroid (HPT) axis, see IPCS Chapter 3 , sections 3.2.1, page 11, 3.3.1, page 13, 3.4.1, page 17 and 3.5.1, page17

For a clear overview of the endocrine system, we recommend the EMcom website : www.emcom.ca/primer/index.shtml 

1.2 What is the definition of endocrine disruptors?

The source document for this Digest states:

Endocrine disruption is not considered a toxicological end point per se but a functional change that may lead to adverse effects. For the purposes of this document, a slight modification of the Weybridge (1996) definition was used and endocrine disruptors are defined in a generic sense as follows:

An endocrine disruptor is an exogenous substance or mixture that alters function(s) of the endocrine system and consequently causes adverse health effects in an intact organism or its progeny or (sub)populations.

A potential endocrine disruptor is an exogenous substance or mixture that possesses properties that might be expected to lead to endocrine disruption in an intact organism, or its progeny, or (sub)populations.

Source & ©: IPCS "Global Assessment of the state-of-the-science of Endocrine disruptors  "
 Executive Summary (Chapter 1) page 1 section 1.1

For further details on endocrine disruptors, see the following website:
www.emcom.ca/EM/index.shtml 

1.3 Why is there concern about endocrine disruptors?

The source document for this Digest states:

The last two decades have witnessed growing scientific concerns and public debate over the potential adverse effects that may result from exposure to a group of chemicals that have the potential to alter the normal functioning of the endocrine system in wildlife and humans. Concerns regarding exposure to these EDCs are due primarily to:

  • adverse effects observed in certain wildlife, fish, and ecosystems;
  • the increased incidence of certain endocrine-related human diseases;
  • endocrine disruption resulting from exposure to certain environmental chemicals observed in laboratory experimental animals.

These concerns have stimulated many national governments, international organizations, scientific societies, the chemical industry, and public interest groups to establish research programs, organize conferences and workshops, and form expert groups and committees to address and evaluate EDC-related issues.

Source & ©: IPCS "Global Assessment of the state-of-the-science of Endocrine disruptors "
 Executive Summary (Chapter 1) page 1 section 1.1

For further details on why there are concerns about EDCs, see IPCS  Chapter 1, section 1.1, page 1.


FacebookTwitterEmail
Themes covered
Publications A-Z
Leaflets

Video