Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Environ Sci Technol. 2010 Mar 1;44(5):1854-9. doi: 10.1021/es9030134.
alpha-HCH (hexachlorocyclohexane) is chiral and can still be detected in almost all environmental media. In this study, the enantioselective behavior of alpha-HCH in mice (CD1) and quail (Coturnix japonica) was investigated and compared after a single dose of exposure. The primary nerve cell culture was conducted to evaluate the enantioselective metabolic capacity of nerve cells of mouse and quail for alpha-HCH. In various tissues of the mice and quail, the alpha-HCH concentrations showed a typical pattern of first-order dynamics after exposure. The enantiomeric fractions (EFs) in nonbrain tissues of mice decreased substantially, indicating continuous depletion of (+)-alpha-HCH in mice. Tissue-specific EF trends in quail and enantioselective degradation of (-)-alpha-HCH in quail liver were observed. These observations indicated that the dynamic changes of EFs in mice and quail were independent of concentration changes in the same tissues. In brain tissues, the enantioenrichment of (+)-enantiomer was totally independent of their concentrations in blood. The in vitro metabolism of alpha-HCH in the primary nerve cells were negligible, and the slight EF changes in primary nerve cells demonstrated that metabolism, uptake, and excretion in the brain cells would not lead to the observed dramatic enantioenrichment of (+)-alpha-HCH in the brain tissues of the two animals. The enantioselective transport across the blood-brain barrier was the primary cause for the enantioenrichment of (+)-alpha-HCH in the brain tissues.
α-六氯环己烷（hexachlorocyclohexane，α-HCH）具有手性，几乎可以在所有环境介质中检测到。本研究采用单次染毒的方式，对比研究了α-HCH 在 CD1 小鼠和 Coturnix japonica 鹌鹑体内的立体选择性行为。通过原代神经细胞培养，评估了α-HCH 在小鼠和鹌鹑神经细胞中的立体选择性代谢能力。在染毒后，小鼠和鹌鹑的各组织中α-HCH 浓度均呈现出典型的一级动力学特征。染毒后，小鼠非脑组织中的对映体分数（enantiomeric fraction，EF）明显降低，表明 (+)-α-HCH 持续耗竭。在鹌鹑组织中观察到了组织特异性的 EF 趋势，并且 (-)-α-HCH 在鹌鹑肝脏中发生了立体选择性降解。这些结果表明，EF 在小鼠和鹌鹑体内的动态变化与同一组织中浓度的变化无关。在脑组织中， (+)-对映体的富集完全与其在血液中的浓度无关。原代神经细胞中α-HCH 的代谢非常少，原代神经细胞中 EF 的轻微变化表明，代谢、摄取和排泄不会导致两种动物脑组织中 (+)-α-HCH 的明显富集。血脑屏障的立体选择性转运是 (+)-α-HCH 在脑组织中富集的主要原因。
