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Endocrine disruptors are exogenous substances affecting the
endocrine system of organisms, resulting in adverse effects.
Excluding the pharmacology of synthetic hormones, however, no
substance has been demonstrated to disrupt the human endocrine
system. This situation has remained unchanged since the
publication of the Supplement to the Intermediary Report in
2001.
The actions taken according to the Supplement to the
Intermediary Report and the remaining major tasks are summarized
below.
(1) Test scheme (Test and evaluation system on health
effects)
[Results]
1) (i) In silico screening (prediction via computer), (ii) in
vitro screening using cellular and non-cellular systems, and
(iii) in vivo screening using ovariectomized animals, juvenile
animals, and castrated animals were conducted.
2) Methodologies for the detailed tests are under development
for comprehensive examination of the growth process of organisms
(embryo - neonate - puberty) and biological reactions (changes
in the neural, endocrine, immune, and other higher systems).
[Future tasks]
1) Developing guidelines and evaluation criteria for specific
tests.
2) Improving screening techniques for higher precision and
comprehensiveness, aiming at a more precise ordering of
substances whose hormonal activities (including those at low
doses) can be biologically explained.
3) For this purpose, adding androgen and thyroid receptors to
the screening system currently involving estrogen receptors.
4) Studying the possibility of pathway screening using
microarray technology.
5) Developing a method for the lifelong monitoring of rodents,
in order to take into account the genesis, development,
maturation, and aging of the neural, endocrine, and immune
network, which will be a part of the definitive studies.
6) Assessing the risk for possible disruptors of the human
endocrine system, to determine appropriate legal or
administrational measures such as limitation of application or
surveillance, with the actual exposure situations taken into
account.
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