Endocrine Disrupting Chemicals (EDCs)

Slides provided by Cynthia Gulledge, University of Louisville, Kentucky

Lafayette CollegeCE 372

Design II/Environmental Site Assessment

Endocrinology: study of hormones

Gland Transport

Target Cell

Hormone

General Features of the endocrine system:

ductless

rich blood supply

secreted into the blood

can reach virtually every cell in the body

hormone receptors are very specific

Endocrine Glands

don’t forget the heart, placenta, fat

All of these glands produce hormones and are also targets for hormones

ENDOCRINE SYSTEMENDOCRINE SYSTEM

HORMONESHORMONESChemical MessengersChemical MessengersSecreted By Glands Secreted By Glands

(pituitary, ovary, testis, adrenal)(pituitary, ovary, testis, adrenal)Into the Bloodstream Into the Bloodstream

Chemical Confusion

• Environmental chemicals can trick or confuse the body into thinking they are natural body chemicals

Symantec Confusion

• Endocrine disrupting chemicals (EDCs)• Hormonally-active agents• Environmental estrogens• Environmental hormones• Environmental chemicals• Environmental signaling

McLachlan, J.A. 2001 Environmental Signaling: What Embryos and Evolution Teach Us About Endocrine Disrupting Chemicals, Endocrine Reviews 22(3): 319-341.

Functional or Receptor-Based Toxicology

Sources of Hormonally-Active Compounds

Pesticide application

Feedlot runoff (hormones, pharmaceuticals)

Agriculture

Industry/Urbanization

Sewage effluent (hormones, pharmaceuticals)

Industrial solvents, effluent

Plasticizers

“Natural”Phytoestrogens

Personal care products (hair and skin care)

Pesticide application (lawns, golf courses)

Sexual Differentiation in Mammals

Organizational Effect of HormonesIf something goes wrong with testis formation, the rest of sexual differentiation is affected in the male

Take-Home Message

Infertility / subfertilityReproductive abnormalities in wildlife and humans

Many hormonally-active compounds in environment

Estrogens, anti-androgens, etc.

Feminization

Advanced puberty

Sources include agriculture, industry, plants

These compounds cause reproductive abnormalities in lab

This evidence forms the basis of the endocrine disrupter hypothesis

e.g., testicular dysgenesis, infertility, feminization