Effect of 2,4-Dichlorophenoxy Acetic Acid on Vitellogenin Synthesis and $E_2$-ER Binding Affinity of Hepatocytes in Rainbow Trout (Oncorhynchus mykiss)

무지개송어, Oncorhynchus mykiss 배양 간세포에서 2,4-Dichlorophenoxy acetic acid이 Vitellogenin 합성과 $E_2$-ER Binding Affinity에 미치는 영향

Effect of 2,4-Dichlorophenoxy acetic acid (2,4-D) on vitellogenin (VTG) production and estrogen ($E_2$)-estrogen receptor (ER) binding affinity were examined in primary hepatocyte cultures of rainbow trout, Oncorhynchus mykiss. Hepatocytes were pre-cultured for 2 days; subsequently, $E_2$( 2$\times$$10^{-6}$/ M) and 2,4-D ($10^{-9}~10^{-6}/M$) were simultaneously added to the incubation medium. They were cultured for more than 5 days. VTG and $E_2$-ER binding affinities were analyzed by SDS-PAGE and ELISA, respectively. 2,4-D concentration used had no appreciable effect on the morphology, viability, and DNA content of hepatocytes in culture. It had also no effect on VTG production. However, it interfered with $E_2$-ER binding affinity, which was reduced with increasing concentration of 2,4-D. The affinity was inhibited by 25 and 30% at $10^{-7}$ M and $10^{-6}$ M of 2,4-D, respectively. This result suggested that although 2,4-D had no effect on VTG production, it acted as reno-estrogenic contaminant in ER.

이 연구는 무지개송어, O. mykiss 간세포 배양을 이용해 합성화학물질인 2,4-Dichlorophenoxy acetic acid (2,4-D)가 vitellogenin (VTG) 합성과 estrogen (E$_2$) - estrogen receptor (ER) binding affinity에 미치는 영향을 조사하였다. 간세포는 2일간 전 배양한 후에 E, (2$\times$10$\^$-6/ M) 또는 2,4-D (10$\^$-9/∼10$\^$-6/ M)를 배지에 첨가해 5일간 배양한 후, VTG과 E$_2$-ER binding affinity를 SDS-PAGE와 ELISA를 이용해 각각 조사하였다. 사용된 2,4-D의 농도는 세포의 형태, 생존력 및 DNA 함량에는 영향을 미치지 않았다. 또한, 2,4-D는 VTG의 합성에도 어떠한 영향도 미치지 않았으나 E$_2$-ER binding affinity를 억제하였다. 이 binding affinity는 2,4-D의 농도가 증가할수록 증가하는 경향을 나타내어 10$\^$-7/과 10$\^$-6/ M에서 25%와 30%를 각각 억제하였다. 이 결과들은 비록 2,4-D가 VTG의 합성에는 영향을 미치지 않지만, ER에서 xeno-estrogenic contaminant로서 행동하는 것을 제시하였다.