Novel Calbindin-D(9k) protein as a useful biomarker for environmental estrogenic compounds in the uterus of immature rats.
The compounds that bind the estrogen receptors (ER) and induce or modulate an ER-mediated response can be defined as estrogenic endocrine disruptors (EDs). We demonstrated that environmental estrogens induced the uterine CaBP-9k mRNA in rats using Northern blot assay suggesting that CaBP-9k gene could be a biomarker for the estrogenicity of chemicals in the previous studies. In the present studies, we further collaborated this idea by investigating the regulation and localization of CaBP-9k protein in response to estrogenic compounds. Immature rats were injected with estrogenic chemicals, 4-tert-octylphenol (OP), nonylphenol (NP) and bisphenol A (BPA) or 17beta-estradiol (E2). After treatment with these estrogenic compounds, the effects on the accumulation of CaBP-9k protein and uterine localization were examined by Western blot analysis and immunohistochemical staining (IHC), respectively. A dose- and time-dependent increase in CaBP-9k protein was observed in the uterus of immature rats when treated with OP and NP. In addition, treatment with BPA resulted in a significant increase in CaBP-9k protein at dose of 500mg/kg BW/day. Taken together, CaBP-9k protein is strongly up-regulated by estrogenic compounds (OP, NP and BPA) and E2 itself in the uterus of immature rats. These results indicate that CaBP-9k protein can be a useful biomarker for detection of the estrogenicity of putative estrogenic compounds. Thus, regarding to risk assessment, we propose that CaBP-9k protein assay in the immature rat uterus can be a very sensitive and powerful tool to identify compounds with estrogenic activity when used in combination with classical assays.
An
Beum-Soo
BS
Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine and Research Institute of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763, Chungbuk, Republic of Korea.
Choi
Kyung-Chul
KC
Kang
Sung Keun
SK
Hwang
Woo Suk
WS
Jeung
Eui-Bae
EB
D000818:Animals; D001559:Benzhydryl Compounds; D015415:Biomarkers / Q000032:analysis; D015153:Blotting, Western; D064026:Calbindins; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000633:toxicity*; D004958:Estradiol / Q000494:pharmacology; D004968:Estrogens, Non-Steroidal / Q000633:toxicity*; D005260:Female; D007150:Immunohistochemistry; D007279:Injections, Subcutaneous; D010636:Phenols / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D064030:S100 Calcium Binding Protein G / Q000032:analysis / Q000096:biosynthesis*; D013997:Time Factors; D014599:Uterus / Q000187:drug effects* / Q000378:metabolism; D000098826:Bisphenol A Compounds
D001559:Benzhydryl Compounds; D015415:Biomarkers; D064026:Calbindins; D004785:Environmental Pollutants; D004958:Estradiol; D004968:Estrogens, Non-Steroidal; D010636:Phenols; D064030:S100 Calcium Binding Protein G; C025256:nonylphenol; C105260:4-tert-octylphenol; C006780:bisphenol A; D000098826:Bisphenol A Compounds