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
