Paraquat uptake in the cultured gastrointestinal epithelial cell line, IEC-6.
Paraquat uptake in the cultured gastrointestinal epithelial cell line, IEC-6.
复制标题
培养的胃肠道上皮细胞系 IEC-6 中的百草枯吸收。
DOI：
10.1006/taap.1993.1176
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发表时间：
1993
影响因子：
3.8
通讯作者：
Seidel,ER
中科院分区：
文献类型：
--
作者：
Grabie,V;Scemama,JL;Robertson,JB;Seidel,ER
虽然百草枯毒性的主要靶器官是肺，但吸收除草剂的主要途径是通过胃肠道上皮。因此，研究了百草枯在大鼠十二指肠隐窝细胞系IEC-6中的摄取情况。除草剂有毒；细胞数测定，ld50为75 μM。以2 μM [14C]百草枯为示踪剂，在37℃条件下，24小时内对该除草剂的吸收缓慢，但呈线性。在4°C时未观察到堆积。抑制研究表明，百草枯抑制腐胺和亚精胺摄取仅15分钟后。在百草枯的作用下，腐胺的km值增加，而vmax没有变化，这表明了一种竞争性的抑制模式。相反，腐胺也抑制百草枯的摄取（IC5010 μM）。假定的钙调蛋白拮抗剂W-7以剂量依赖性的方式减少了百草枯的摄取，但不受Ca2+/钙调蛋白激酶II特异性抑制剂KN-62的影响。这些结果提供了证据，证明百草枯的摄取是通过IEC-6细胞的多胺运输系统发生的。此外，这一过程是由细胞内事件调节的，涉及一个主要的信号蛋白，Ca2+/钙调蛋白。
Although the major target organ of paraquat toxicity is the lung, the primary route of absorption of the herbicide is across the gastrointestinal epithelium. Thus, uptake of paraquat was investigated in the rat duodenal crypt cell line, IEC-6. The herbicide was toxic; as measured by cell number, the LD50was 75 μM. Using 2 μM [14C]paraquat as tracer, uptake of the herbicide was found to be slow but linear over 24 hr at 37°C. No accumulation was observed at 4°C. Inhibition studies showed paraquat inhibited both putrescine and spermidine uptake after only a 15-min incubation. The Kmfor putrescine was increased when incubated in the presence of paraquat whereas Vmaxwas not changed, suggesting a competitive mode of inhibition. In the reverse situation, putrescine also inhibited paraquat uptake (IC5010 μM). Paraquat uptake was reduced in a dose-dependent manner by the putative calmodulin antagonist W-7, but was not affected by KN-62, a Ca2+/calmodulin kinase II specific inhibitor. These results provide evidence that paraquat uptake occurs through the polyamine transport system in IEC-6 cells. Furthermore, this process is modulated by intracellular events involving a major signaling protein, Ca2+/calmodulin.