Younglai E V, Kwan T K, Kwan C-Y, Lobb D K, Foster W G
Department of Obstetrics & Gynecology, Reproductive Biology Division, McMaster University, Health Sciences Centre, Hamilton, Ontario, Canada.
Biol Reprod. 2004 Jun;70(6):1693-700. doi: 10.1095/biolreprod.103.026187. Epub 2004 Feb 6.
1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a metabolite of DDT (1,1-dichlorodiphenyltrichloroethane), is a persistent hormonally active environmental toxicant that has been found in human serum and follicular fluid. The objective of this study was to determine whether DDE can alter free calcium ion concentrations in the cytosol (Ca(2+)) of human granulosa cells. Changes in Ca(2+) in single cells loaded with Fura-2 were studied using a dynamic digital Ca(2+) imaging system. At a concentration of 100 ng/ml, DDE stimulated small elevations of Ca(2+) accompanied by Ca(2+) oscillations. At 1 microg DDE/ml, there was a biphasic Ca(2+) response with marked elevations of Ca(2+) over time. In Ca(2+)-free medium, cells showed an initial small elevation of Ca(2+), which was magnified after addition of Ca(2+) to the medium. Washing the cells after DDE treatment failed to remove the elevated Ca(2+) and oscillations, both of which were eliminated by addition of EGTA. ATP also induced Ca(2+) elevations and oscillations, and these effects were potentiated when DDE was added. FSH induced transient Ca(2+) elevations, whereas hCG caused a prolonged elevation and marked oscillations in Ca(2+). These results suggest that DDE at concentrations normally found in human tissues induces elevations in Ca(2+) in granulosa-lutein cells. Our data therefore highlight a novel mechanism through which DDE can alter endocrine homeostasis and possibly act as an endocrine toxicant.
1,1-二氯-2,2-双（对氯苯基）乙烯（DDE）是滴滴涕（1,1-二氯二苯基三氯乙烷）的一种代谢产物，是一种具有激素活性的持久性环境毒物，已在人体血清和卵泡液中被发现。本研究的目的是确定DDE是否能改变人颗粒细胞胞质溶胶中游离钙离子浓度（Ca(2+)）。使用动态数字钙（Ca(2+)）成像系统研究了加载Fura-2的单细胞中Ca(2+)的变化。在浓度为100 ng/ml时，DDE刺激Ca(2+)出现小幅升高并伴有Ca(2+)振荡。在1 μg DDE/ml时，出现双相Ca(2+)反应，随着时间推移Ca(2+)显著升高。在无钙培养基中，细胞显示Ca(2+)最初有小幅升高，在向培养基中添加Ca(2+)后该升高被放大。DDE处理后洗涤细胞未能去除升高的Ca(2+)和振荡，添加EGTA后两者均被消除。ATP也诱导Ca(2+)升高和振荡，添加DDE时这些效应会增强。促卵泡激素（FSH）诱导Ca(2+)短暂升高，而人绒毛膜促性腺激素（hCG）导致Ca(2+)持续升高并伴有明显振荡。这些结果表明，在人体组织中通常发现的浓度下，DDE可诱导颗粒黄体细胞中Ca(2+)升高。因此，我们的数据突出了一种新机制，通过该机制DDE可改变内分泌稳态并可能作为一种内分泌毒物发挥作用。
