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[Future tasks]
1) The following should be promoted for clarification of the
low-dose issue.
- Studies for securing reproducibility of detection of
hormone-like actions by agents at low doses
- Studies for elucidation of mechanisms of action and
determination of evaluation criteria of endocrine disruption by
exposure at the highly sensitive fetal, neonatal and adolescent
periods
- Systematic and continuous information gathering on reported
action by low doses in highly sensitive periods; studies for
interpretation of research results in terms of (i) threshold
problem, (ii) non-linear dose-response relationships, and (iii)
additive reactions.
- Studies on effects on the homeostatic regulatory systems, i.e.
immune, thyroid-CNS and behavioral systems
- Studies on genomic findings
2) A comprehensive guideline should be developed concerning
evaluation of test results on the endocrine disrupting activity.
(4) Epidemiologic study of exposure
4.1 Degree of exposure of living bodies
[Results]
1) Concentrations in biological samples (blood, urine, hair,
etc.) of the following substances:
Bisphenol A, chlorobenzenes, p-hydroxybenzenes, phthalic acid
esters, benzo[a]pyrene, PCBs, dioxins, chlordane, organotin
compounds, 4-nonylphenol, halogenated hydrocarbon pesticides,
organophosphate pesticides, organochlorine pesticides,
organofluorine compounds, phytoestrogens, heavy metals, and
volatile organic compounds. (Subjects and biological samples are
not common to all the substances.)
Each of these substances (except chlordane) is found in some or
other biological samples, indicating possibility of
environmental exposure.
2) Studies indicated that metabolic process eliminates bisphenol
A rapidly from the blood and convert phthalates into mono- or
diethyl derivatives.
[Future tasks]
1) Continuing study on exposure via the maternal body by
accumulating analytical data on suspected endocrine disruptors
in the environment in various biological samples (including cord
blood) from the same mothers.
2) Elucidating expression of effects on the living body,
metabolism and detoxification of the chemical agents in the
range of body burden.
3) Regularly monitoring the concentrations in the environment
(background level) of the agents in parallel with analysis for
evaluating effects of exposure.
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