PHY3181 Lecture Notes - Lecture 9: Aromatase, Estradiol, Plasticizer
30 Jun 2018
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Lecture 15: endocrine disruptors and
reproduction
EDCs are an international and political issue:
scientific societies such as the endocrine
society should partner with other
organisations with the scientific and medical
expertise to evaluate effects of EDCs in
humans.
EDCs can pose a threat to reproductive health
and children’s growth and development.
EDCs = a compound, either natural or
synthetic, which through environment or
inappropriate developmental exposures alters
the hormonal and homeostatic systems that
enable the organism to communicate with and
respond to its environment
(can be from food, environment ect)
Examples
• Plant steroids – phytoestrogens
• Components of detergent
• Leached from plastics – BPA,
nonylphenol, phthalates
• Pesticides and fungicides
• Polycholorinated chemicals from
industry – bisphenols
EDCs and the body
• The impact of EDCs are complex and
subtle
• Almost impossible to prove that any
particular EDC is causing biological
changes
• EDCs combine tiny effects to cause
damage
• All endocrine and hormonal systems
are vulnerable
• EDCs alter reproductive function by
activating steroid receptors such as
AR, ER and PR – they can mimic or
block these
Possible diseases that may have EDC
influences: CVD, type 2 diabetes, obesity,
thyroid disorders, cancer
Challenges in EDC research
• Exposure is difficult to measure - there
are known and unknown EDC
exposures
• Individual differences
• There is a large time lag
• The exact role of hormones is not fully
defined
EDCs interfere with foetal growth and
development while bodies organs and tissues
are still developing
EDCs challenge traditional concepts in
toxicology
Typically, only see consequences above a
certain level when looking at toxins. With EDCs
there are is biphasic response – can have
effects at low doses that are not predicted by
effects at higher doses.
Note that the issue of dose-response
relationships is perhaps the most controversial
issue regarding EDCs.
Low dose plastics induce the most severe
phenotype in the testis and prostate.
Exposure to EDCs has greatest effect on fetal/
neonatal development.
EDCs were discovered by effects in sheep
eating sweet clover (has an EDC –
phytoestrogen). Phytoestrogens are an
estrogen like compound that activates the
estrogen receptors causing endocrine
disruption. Phytoestrogens are used in
therapeutics eg for the treatment of CVS
they have strict dosage and timing.
EDCs can have short term effects these
were observed in clovers disease which
Document Summary
Edcs are an international and political issue: scientific societies such as the endocrine society other organisations with the scientific and medical expertise to evaluate effects of edcs in humans. partner with should. Edcs can pose a threat to reproductive health a(cid:374)d childre(cid:374)"s gro(cid:449)th a(cid:374)d de(cid:448)elop(cid:373)e(cid:374)t. Edcs = a compound, either natural or synthetic, which through environment or inappropriate developmental exposures alters the hormonal and homeostatic systems that enable the organism to communicate with and respond to its environment (can be from food, environment ect) Examples: plant steroids phytoestrogens, components of detergent from plastics. Leached nonylphenol, phthalates: pesticides and fungicides, polycholorinated chemicals. Ar, er and pr they can mimic or block these that may have edc. Possible diseases influences: cvd, type 2 diabetes, obesity, thyroid disorders, cancer: exposure is difficult to measure - there known and unknown edc are exposures. Individual differences: there is a large time lag, the exact role of hormones is not fully defined interfere with.
