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Advisory Committee on Health Effects of Endocrine Disruptors
The Supplement II to the Intermediary Report
1.1.3 |
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(b) In vitro screening (ii)
1) Cellular systems
Reporter gene tests using mammal-derived cell cultures1
Reporter gene tests using mammal-derived cell cultures,
including HeLa and CHO cells, were tested as a screening method
for hormone receptor-dependent protein synthesis induction.
These tests yielded 500, 100, 50 and 50 assay results,
respectively, for ERα, ERβ, androgen receptor (AR) and thyroid
hormone receptor (TR)β (a combination of TRβ with retinoid X
receptor (RXR)α).
Other tests2
Substances that suppress or promote the aromatase (estrogen
synthesis) activity of KGN cells, one of the human ovarian
granulosa cells, were identified out of 55 compounds. A new
technique to determine aromatase activity based on ELISA
(enzyme-linked immunosorbent assay) using KGN cells was
developed, which is more sensitive and easier to perform than
the conventional 3H-water method. This technique identified
aromatase inhibitors among 100 compounds.
As for andogen receptors (ARs), a new detection system of
anti-androgen activity, based on the AR dot distribution in the
nucleus, transfer of activin receptor cell strains, and
migration capability of primordial germ cells, is being
developed.
2) Non-cellular systems
SPR (surface plasmon resonance) studies of the interaction
between receptors, ligands, DNA responsive elements (ERE) and
coupling factor binding sequences (LxxLL) are underway: 300, 30,
300, and 30 measurements were made, respectively, for ERα + ERE,
ERβ + ERE, ERα + TF-2, and ERβ + TF-2. These data are used as
subsidiary data in the screening tests (i), (ii) and (iii) as
well as for evaluation of the screening results.
Substances chosen for study for establishment of guidelines and
evaluation criteria (potential positives) are those exist in the
natural environment or the environment of human life, for which
any endocrinological effect has been observed in wildlife or
experimentally found. The screening method for these substances
should be capable of determining the intensity of the effect
with precisions sufficient for elucidation of the mechanism of
action. The methods that meet this requirement are to be
proposed for domestic and/or international (pre-)validation,
through which the guidelines will be finalized. |
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1 Report
of studies supported by the Health and Labour Sciences Research
Grants (led
by Jun Kanno)
2 Report of studies supported by the
Health and Labour Sciences Research Grants (led by Arata Nawada) |
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