Endocrine Disrupting Investigations of Six Pesticides with Estrogen Receptor Binding Assays and Uterotrophic Effects in Rats

以體外雌激素受體結合與大鼠子宮激性測試評估六種農藥之內分泌干擾作用

呂水淵(Shui-Yuan Lu) ； 蔡韙任(Wei-Ren Tsai)

《臺灣農藥科學》 5期 (2018/12) Pp. 31-51

https://doi.org/10.6671/TPS.201812_(5).03

摘要

The previous reports showed that estrogen receptor played an important role in reproductive toxicity in rats. Estrogen receptor disrupting is one of important endocrine disrupting (ED) issue. Due to the in vitro estrogen binding assay with radioisotope it was unfriendly to most of laboratories in spite of reducing animals. We aimed to make sure if the uterotrophic assay can cover the in vitro method for ED screening with six reported reproductive toxicity and ED pesticides including permethrin, endosulfan, cypermethrin, methyl parathion, benomyl and carbendazim. The results showed that in the estrogen receptor competitive binding assay the inhibition concentration with the half maximal inhibitory concentration (IC_(50)) were 141, 249, 523, 1022, 1413 and 4334 μM in permethrin, endosulfan, cypermethrin, methyl parathion, benomyl and carbendazim, respectively. This implied that permethrin, endosulfan and cypermethrin showed estrogen receptor affinity without identification of agonist or antagonist while methyl parathion, benomyl and carbendazim exhibited none to weak estrogenic. In the uterotrophic assay permethrin exhibited significantly antiestrogenic while endosulfan showed approaching estrogen receptor agonist. As the permethrin did cypermethrin exhibited significantly antiestrogenic activity while methyl parathion did not. Both benomyl and carbendazim showed estrogenic-like agonist. In comparison with endpoint of estrogen receptor binding and uterotrophic assay in these pesticides revealed that the coincidence existed in permethrin, cypermethrin, and methyl parathion and even in endosulfan. It seems that the coincidence of estrogen receptor binding and uterotrophic assay did not exist in benomyl and carbendazim. That is because the uterotrophic effect was induced by benomyl and carbendazim through androgen receptor activation referring to our previous reports. This study concluded that in terms of estrogen receptor affinity the order is permethrin ＞ endosulfan ＞ cypermethrin ＞ methyl parathion ＞ benomyl ＞ carbendazim. The final outcome should depend on the in vivo study, uterotrophic assay. Permethrin and cypermethrin exhibited anti-estrogenic activity while endosulfan showed weak estrogenic activity and methyl parathion did not. Benomyl and carbendazim increased uterus fluid through androgenic activity. Based on above we suggest that uterotrophic test not only can cover the in vitro estrogen receptor binding assay but show more friendly and robust than in vitro method as well.

關鍵字

Cypermethrin ； Permethrin ； Endosulfan ； Methyl parathion ； Benomyl ； Carbendazim

並列摘要

過去文獻顯示雌激素受體在生殖毒性中扮演重要角色，雌激素受體干擾乃內分泌干擾重要因子之一，由於體外受體結合測試雖可減少動物需求量但使用放射性標幟方法造成一般實驗室不便性，因此本試驗目的在探討以文獻報導具生殖毒或內分泌干擾作用之賽滅寧、百滅寧、安殺番、甲基巴拉松、貝芬替及免賴得等6種農藥進行兩種方法比對，是否大鼠子宮激性測試可涵蓋體外雌激素受體結合試驗結果。結果顯示，在體外雌激素受體結合競爭性試驗，抑制半數濃度值（IC_(50)）在百滅寧、安殺番、賽滅寧、甲基巴拉松、免賴得及貝芬替分別為141、249、523、1022、1413及4334μM，此意謂百滅寧、安殺番及賽滅寧較具雌激素受體親和作用，但無法辨別是促進或拮抗作用，而甲基巴拉松、免賴得及貝芬替則偏弱到無雌激素受體親和作用。在大鼠子宮激性試驗，百滅寧顯著拮抗雌激素作用而安殺番則接近促進雌激素作用。賽滅寧同百滅寧一樣顯著顯現拮抗雌激素作用，而甲基巴拉松則無明顯影響。免賴得與貝芬替均顯著顯現類似雌激素作用，比較各農藥在體外雌激素受體結合競爭性試驗與大鼠子宮激性試驗結果，百滅寧、賽滅寧、甲基巴拉松甚至安殺番在體外與體內試驗結果相符。至於免賴得與貝芬替在體外與體內試驗結果似乎不符，但參考過去文獻可知，免賴得與貝芬替在大鼠子宮激性作用乃因其雄性素激性作用所致。綜合上述結果，就與雌激素受體親和性而言，百滅寧＞安殺番＞賽滅寧＞甲基巴拉松＞免賴得＞貝芬替，但就活體內試驗結果，百滅寧與賽滅寧具拮抗雌激素受體作用而安殺番有弱促進雌激素受體作用，甲基巴拉松則無明顯作用，免賴得與貝芬替則透過雄性素受體誘發類雌激素受體作用，推論雌、雄激素受體在生殖毒性扮演重要角色。同時本研究也得到一結論，大鼠子宮激性可涵蓋體外以放射線標幟雌激素受體測試結果，增加以大鼠子宮激性試驗取代體外雌激素受體干擾篩選之友善與功能性。

並列關鍵字

賽滅寧 ； 百滅寧 ； 安殺番 ； 甲基巴拉松 ； 免賴得 ； 貝芬替