1. Endocrine Disrupting Chemicals (EDCs)
Lafayette College
CE 372
Design II/Environmental Site Assessment
Slides provided by Cynthia Gulledge, University of Louisville, Kentucky

2. Endocrinology: study of hormones
General Features of the endocrine system:
Transport
Gland
Endocrinology is the study of the endocrine system
Glands secrete hormones into the blood stream, which then travel to the tissues where they bind to receptors on target cells and have effects
The endocrine system has several general features………
-ductless (think of glands that have ducts…those are EXOCRINE glands…secrete outside the body)
ergo, they need a rich blood supply
-secreted into the blood (not outside the body or just to neighboring cells)
-hormone receptors are very specific
Hormone
Target Cell
rich blood supply
hormone receptors are very specific
secreted into the blood
ductless
can reach virtually every cell in the body

3. Endocrine Glands
don’t forget the heart, placenta, fat
All of these glands produce hormones and are also targets for hormones
All of these glands produce hormones and are also targets for hormones
Don’t forget the heart! (ANF) and the placenta (human chorionic gonadotropin, progesterone), and fat (estrogen, leptin)

4. (pituitary, ovary, testis, adrenal)
ENDOCRINE SYSTEM
HORMONES
Chemical Messengers
Secreted By Glands
(pituitary, ovary, testis, adrenal)
Into the Bloodstream

5. Chemical Confusion
Environmental chemicals can trick or confuse the body into thinking they are natural body chemicals

6. Symantec Confusion Endocrine disrupting chemicals (EDCs)
Hormonally-active agents
Environmental estrogens
Environmental hormones
Environmental chemicals
Environmental signaling

7. Functional or Receptor-Based Toxicology
McLachlan, J.A Environmental Signaling: What Embryos and Evolution Teach Us
About Endocrine Disrupting Chemicals, Endocrine Reviews 22(3):

8. Sources of Hormonally-Active Compounds
Agriculture
Pesticide application
Feedlot runoff (hormones, pharmaceuticals)
Industry/Urbanization
Plasticizers
Industrial solvents, effluent
Sewage effluent (hormones, pharmaceuticals)
Personal care products (hair and skin care)
Pesticide application (lawns, golf courses)
“Natural”
Phytoestrogens

9. Sexual Differentiation in Mammals
Organizational Effect of Hormones
If something goes wrong with testis formation, the rest of sexual differentiation is affected in the male

10. This evidence forms the basis of the endocrine disrupter hypothesis
Take-Home Message
Reproductive abnormalities in wildlife and humans
Infertility / subfertility
Feminization
Advanced puberty
Many hormonally-active compounds in environment
Estrogens, anti-androgens, etc.
Sources include agriculture, industry, plants
These compounds cause reproductive abnormalities in lab
e.g., testicular dysgenesis, infertility, feminization
This evidence forms the basis of the endocrine disrupter hypothesis