Calbindin-D9k mRNA expression in the rat uterus following exposure to methoxychlor: a comparison of oral and subcutaneous exposure.
Calbindin-D(9k) (CaBP-9k) is a cytosolic calcium-binding protein that is induced by estrogenic compounds possibly through estrogen receptors. We compared CaBP-9k mRNA expression in the uterus with uterotrophic response in immature rats exposed to methoxychlor (MC), an environmental chemical with estrogenic activity. MC was orally or subcutaneously administered to 3-week-old female Sprague-Dawley rats for 3 days. The weights of the uterus and vagina significantly increased in the oral treatment group at a dose of 50, 100 and 200 mg/kg, but those of the subcutaneous (SC) treatment group only increased at 200 mg/kg. Northern blot analysis showed that CaBP-9k mRNA expression was significantly induced in a dose-dependent manner at doses of 50, 100 and 200 mg/kg/day in the oral treatment group. SC administration of MC induced significant expression at only a dose of 200 mg/kg/day; this was similar to the uterotrophic response. MC has an estrogenic effect on the uterus as shown by the increase in weight and induction of CaBP-9k mRNA expression, which were much greater following exposure via oral gavage than via the SC route. The strong correlation between the results of in vivo uterotrophic assay and CaBP-9k mRNA expression suggests that CaBP-9k mRNA expression in the rat uterus may be used as an early gene marker for detection of the estrogenic effects of putative environmental chemicals.
Shin
Jae-Ho
JH
Endocrine Toxicology Division, National Institute of Toxicological Research, Korea Food and Drug Administration, Seoul, Korea. jaehoshin@hanmair.com
Moon
Hyun Ju
HJ
Kang
Il Hyun
IH
Kim
Tae Sung
TS
Lee
Su Jung
SJ
Oh
Ji Young
JY
Lee
Young Joo
YJ
Hong
Eui-Ju
EJ
Jeung
Eui-Bae
EB
Han
Soon-Young
SY
D000284:Administration, Oral; D000818:Animals; D064026:Calbindins; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D007279:Injections, Subcutaneous; D008731:Methoxychlor / Q000008:administration & dosage* / Q000097:blood; D009929:Organ Size; D012333:RNA, Messenger / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D064030:S100 Calcium Binding Protein G / Q000187:drug effects* / Q000235:genetics*; D014599:Uterus / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology
D064026:Calbindins; D012333:RNA, Messenger; D064030:S100 Calcium Binding Protein G; C576508:S100g protein, rat; D008731:Methoxychlor