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

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

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)

(pituitary, ovary, testis, adrenal) ENDOCRINE SYSTEM HORMONES Chemical Messengers Secreted By Glands (pituitary, ovary, testis, adrenal) 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

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

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

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

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