EnvironmentalEndocrineDisruptors-ArkansasStateUniversity.ppt

Environmental Endocrine Disruptors 1960’s Eagles Eggshells DDT affected reproduction Mink – Lake Michigan Repro failure Fed lake fish Those fed fish from other sources normal 1970’s Fish-eating birds – Gulf Coast, Great Lakes Abnormalities of repro structures/functions Malformed offspring Women DES daughters Repro cancers Rare cell changes – vagina, oviducts, uteri Repro organ dysfunction/disfigurement Estrogen replacement ? repro effects (DES Potent estrogenic Growth stimulant in cattle Miscarriage prevention in women) Men DES sons Abnormalities of genitalia, sperm Testicular cancer Undescended testicles Kepone spill Low sperm count 1980’s Male alligators DDT 1/2 testosterone Small penis size Repro capacity?? 1990’s Male wildlife Various cmpds in water Sea gulls Eggs exposed to DDT ? female Turtles Eggs exposed to PCB’s ? female Male-producing temps Same as estrogen exposure Fish Polluted water Vitellogenin Egg yolk protein Female fish-laying eggs Also female fish masculinized Laboratory Animal Studies Drugs/toxins @ diff stages neonatal dev’t Sensitive @ spec times of dev’t Irreversibility Too much/too little may be harmful Too little testosterone ? testicular feminization “Behavior sex” of brain If no androgens ? phentypic female Estrogen masculinizes brain Brief exposure ONLY Affects repro ability later in life Detox ? low doses tolerable BUT higher doses overwhelm metab Human sperm count depleted?? 50% drop 1938-1990?? Incr’d human prostate, testicular cancers reported Poss female repro dysfunctions Incr’d human breast, ovarian cancer rates Incr’d PolyCystic Ovarian Disease Related to neonatal androgenization (rodents) ? early onset estrus acyclicity What Are Endocrine Disruptors? EPA “Exogenous substance that changes endocrine function and causes adverse effects at the level of the organism, its progeny and/or (sub)populations of organisms” May act like endogenous hormones OR metabolites can act like hormones OR can block effects of opp sex hormones, growth