what are we learning from wildlife about endocrine disruption that is relevant to human health?
DESCRIPTION
What are we learning from wildlife about endocrine disruption that is relevant to human health? . Dr. Peter L. deFur Center for Environmental Studies Virginia Commonwealth Univ June 20 2013. In A Word. Everything Well… Almost everything Considering all “not people” animals. - PowerPoint PPT PresentationTRANSCRIPT
What are we learning from wildlife about endocrine disruption that is
relevant to human health? Dr. Peter L. deFurCenter for Environmental StudiesVirginia Commonwealth UnivJune 20 2013
In A Word
EverythingWell…
Almost everythingConsidering all “not people” animals
Pesticide companies have disrupted insect hormone systems for ca. 40 years
All good science is a story – of inquiry and discovery Hormonal control of metamorphosis in insects is affected by molting (ecdysone) and juvenile hormones
OH
HO
HOH
O
OH
OH
OHOH
HO
HOH
O
OH
OH
OHOH
HO
HOH
O
OH
OHOH
OH
HO
HOH
O
OH
Ponasterone A
20-HydroxyecdysoneEcdysone
Makinsterone A
OH
HO
HO
OH
OHO
3-dehydroecdysone
OH
HO
HOH
O
OH
25-deoxyecdysoneInsect Juvenile Hormone
Tebufenozide
Ecdysone
O
O
OO
O
O
O
OO
JH-I
JH-II
JH-IIIOO
O
JH-III bis epoxide
O
O
O
methyl farnesoate
OO
O
O
ONH O
O
O
OO N
Methoprene
Fenoxycarb
Pyriproxyfen
O
O
Hydroprene
Two clutches of eggs in one nestCross-billed cormorant In 1993-
6
The Story continues- pick up to the early 1990’s
Beginning with
wildlife in recent years
Mimic normal action Abnormal action Blocked action
hormone
hormone
EDC EDC
EDC
R
R R
R= hormone receptor; EDC = endocrine disrupting chemical
Model of how EDC acts on hormone-receptor interactions
What can go wrong or awry with chemicals in the environment?
Fish sex change
First reported in Florida in 1970’s Male Goby fish showed female characteristics Downstream from pulp mill effluent Sitosterol was active chemical from trees Reported in other rivers with pulp effluent Resurfaced in England in 1995- thanks to
John Sumpter
“steroid” mechanism of action
Second messenger mechanism
How does a system work?
Lessons thus far
Can synthesize hormones and mimics Untimely exposures can harm Endogenous hormones when exogenous— Mechanisms and processes Low levels can harm
Ecy receptor
RxR receptor
17B-Estradiol 20- hydroxyecdysone Diethylstilbestrol (DES)
DDT Coumestrol
BPA
4-nonylphenol17 B estradiol
chlordecone
Tributyltin
Ah receptor model
Lessons learned- some too late
Biology is conserved What can go wrong How disruption occurs New end points New mechanisms Indicators- the canary in the coal mine Need confirmation from mammalian data
Summary of lessons
Birds Reproduction, developmentBehaviour
PCB, TCDD, Cl-
Mammals Reproductiondevelopment
Chlorinated chem.’s
FishAmphibian
Sex determination EE, E, T, A
Invert.’s cross species; growth, development
Juvenile mimics; TBT;
?42