| |
Software Requirements
Microsoft Internet Explorer 5.01 or higher and Netscape Navigator 4.75 or higher are recommended. |
|
 |
J.Health Sci., 50(5), 511-517, 2004
Development of Standardized in Vitro Assay
System for Estrogen Receptors and Species Specificity of Binding Ability of 4-Nonylphenol and p-Octylphenol
Makoto Nishizuka,a Shiro
Heitaku,a Shinobu
Maekawa,a Jun-ichi
Nishikawa,b and Masayoshi Imagawa*, a
aDepartment of Molecular Biology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori,
Mizuho-ku, Nagoya, Aichi 467-8603, Japan and
bLaboratory of Environmental Biochemistry, Graduate School of Pharmaceutical Sciences,
Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
The in vitro binding assay seems to be a useful first screening method for endocrine disrupting chemicals. The
various methods have been developed and applied to the testing of chemicals. Although these assays should be
applied to estrogen receptors (ER) of not only humans but also wildlife, a standardized system is yet to be
established. Furthermore, a method for
Xenopus ER is not yet developed. We previously expressed the ligand-binding
domain (LBD) of quail ER alpha and ER beta as a fusion protein with glutathione S-transferase, and developed a competitive
enzyme immunoassay for detecting the capacity of chemicals to bind ERs. It seems that this system is a powerful
tool, since it needs no special equipment. In this report, we first produced ER-LBD protein of human,
Xenopus and medaka as well as quail. Then, we established a competitive enzyme immunoassay for these ERs as a standardized
method, and compared the species specificity of the ability of 4-nonylphenol and
p-octylphenol to bind ERs. Although a significant difference was not detected among
ER beta of human, quail and medaka, 4-nonylphenol and
p-octylphenol exhibited the higher affinity for the medaka
ER alpha than human ER alpha. These results indicate the species
specificity of the capacity of chemicals to bind ERs.
|
|
