Racay P, Kaplán P, Mézesová V, Lehotský J
Comenius University, Jessenius Faculty of Medicine, Department of Medical Biochemistry, Martin, Slovak Republic.
Biochem Mol Biol Int. 1997 Apr;41(4):647-55. doi: 10.1080/15216549700201691.
Incubation of reticular membranes with Fe(2+)-EDTA and H2O2 plus Fe(2+)-EDTA at 37 degrees C for 30 min led to the loss of membrane's efficiency to sequester Ca2+ to 21.8% and 3.6% of control values, respectively. The incubation of microsomes with Fe(2+)-EDTA and H2O2 plus Fe(2+)-EDTA also caused decrease of Ca(2+)-ATPase activity; to 44.9% and 44.4% (measured under the same conditions as Ca(2+)-uptake) or to 79.6% and 62.1% (uncoupled from Ca2+ transport by detergent). In addition, incubation of membranes with Fe(2+)-EDTA and H2O2 plus Fe(2+)-EDTA at 37 degrees C for 30 min led to the increase of Ca2+ permeability to 125.1% and 124.2%, respectively. Preincubation of membranes with membrane-soluble antioxidants (U-74500A, U-83836E, t-butyl hydroxytoluene and stobadine) protected the reticular membranes against depression of Ca2+ uptake values and Ca(2+)-ATPase inhibition in a dose and an antioxidant nature dependent manner. Our results indicate that both processes, Ca(2+)-ATPase inhibition and increase of endoplasmic reticulum membrane Ca2+ permeability, participate in the lipid peroxidation induced loss of membrane's efficiency to sequester Ca2+.
将网状膜与Fe(2+)-EDTA以及H2O2加Fe(2+)-EDTA在37℃孵育30分钟，导致膜隔离Ca2+的效率分别降至对照值的21.8%和3.6%。微粒体与Fe(2+)-EDTA以及H2O2加Fe(2+)-EDTA孵育也会导致Ca(2+)-ATP酶活性降低；分别降至44.9%和44.4%（在与Ca(2+)摄取相同的条件下测量）或79.6%和62.1%（通过去污剂与Ca2+转运解偶联）。此外，将膜与Fe(2+)-EDTA以及H2O2加Fe(2+)-EDTA在37℃孵育30分钟，导致Ca2+通透性分别增加至125.1%和124.2%。用膜溶性抗氧化剂（U-74500A、U-83836E、叔丁基羟基甲苯和司他汀）对膜进行预孵育，以剂量和抗氧化剂性质依赖的方式保护网状膜免受Ca2+摄取值降低和Ca(2+)-ATP酶抑制的影响。我们的结果表明，Ca(2+)-ATP酶抑制和内质网膜Ca2+通透性增加这两个过程都参与了脂质过氧化诱导的膜隔离Ca2+效率的丧失。
