Hepatic expression of selenium binding protein (SelenBP) in female mice and its inducibility by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was studied using wild-type (WT) C57BL/6J and SelenBP1-knockout mice. Female WT mice (4 weeks old) received TCDD at the dose of 100 mg/kg (i.p.). The control group received the vehicle, corn oil. In addition, SelenBP1-KO mice received TCDD at the same dose as the WT. A control group of SelenBP1-KO mice received the vehicle, corn oil. Five days after treatment, livers were removed and homogenized. The level of SelenBP in the liver homogenate was compared between the control and TCDD-treated groups by immunoblotting using anti-human SelenBP1 antibody as the primary antibody. It has been discovered that there are two SelenBP isoforms in mice, SelenBP1 and SelenBP2. The antibody used was expected to recognize both SelenBP1 and SelenBP2 in mice. The level of SelenBP in the livers of female SelenBP1-KO mice was far lower than those in WT mice. In addition, the level of SelenBP in WT mice was induced to approximately 5 times by TCDD treatment while there was no substantial increase in SelenBP level in SelenBP1-KO mice. Therefore, SelenBP1 is constitutively expressed as the predominant SelenBP isoform in the liver of female WT mice whereas the level of SelenBP2 remains low. In addition, the SelenBP2 is barely induced in the liver of female mice by TCDD. These results suggest that the induction of hepatic SelenBP at the protein level in female mice by TCDD is mainly due to the induction of SelenBP1.はじめに / 実験方法 / 結果 / 考察 / 結
