Elder J H, Morré D J, Yunghans W N
Eur J Cell Biol. 1979 Aug;19(3):231-8.
Sarcoplasmic reticulum fragments capable of accumulating calcium were isolated from rat skeletal muscle by differential and sucrose gradient centrifugation. The ability of these fragments to accumulate calcium was impaired by adding 2,2-bis-(p-chlorophenyl)-1,1,1-trichloroethane (DDT) to the assay medium at concentrations of 0.06 to 6 muM. DDT (6 muM) caused a sharp lag in calcium uptake, with an 82% reduction in reaction rate 30 sec after calcium was added and a 62% reduction after one min. Basal ATPase activity of the microsomal fraction was inhibited by DDT but the calcium-stimulated increment of ATP hydrolysis was not. The findings show that DDT hinders calcium uptake by sarcoplasmic reticulum, but by some means other than inhibition of the calcium-stimulated ATPase. An apparent antagonism between DDT and ouabain or oligomycin was indicated. We propose that the presence of the lipid-soluble DDT molecule within the membrane of the sarcoplasmic reticulum interferes with the normal rapid uptake of calcium ions required for muscle relaxation, and that this interference may contribute to loss of muscle control in organisms poisoned by DDT.
通过差速离心和蔗糖梯度离心从大鼠骨骼肌中分离出能够积累钙的肌浆网片段。在测定培养基中加入浓度为0.06至6μM的2,2-双（对氯苯基）-1,1,1-三氯乙烷（滴滴涕）会损害这些片段积累钙的能力。滴滴涕（6μM）导致钙摄取出现明显延迟，添加钙后30秒反应速率降低82%，1分钟后降低62%。微粒体部分的基础ATP酶活性受到滴滴涕抑制，但钙刺激的ATP水解增加不受影响。研究结果表明，滴滴涕通过某种方式阻碍肌浆网对钙的摄取，而非抑制钙刺激的ATP酶。结果表明滴滴涕与哇巴因或寡霉素之间存在明显的拮抗作用。我们认为，肌浆网膜内脂溶性滴滴涕分子的存在会干扰肌肉松弛所需的钙离子正常快速摄取，这种干扰可能导致滴滴涕中毒生物体肌肉控制丧失。
