硒缺之与大鼠肝脏磷脂氢过氧化物谷胱甘肽过氧化物酶

雄性断奶的Ｗｉｓｔａｒ大鼠，喂养硒缺乏饲料，谷胱甘肽过氧化物酶活性迅速降低，它们降低的顺序是：肝脏经典的谷胱甘肽过氧化物酶（ＧＰｘ）、血浆ＧＰｘ、红血球ＧＰｘ，肝磷脂氢过氧化物谷胱甘肽过氧化物酶（ＰＨＧＰｘ）。凝胶过滤层析表明：大鼠肝胞浆中存在一种能使磷脂氢过氧化物（ＰＣＯＯＨ）还原的ＧＰｘ。但与ＰＨＧＰｘ不同。Ｗｅｓｔｅｒｎｂｌｏｔ分析证明：喂硒缺乏饲料９周的大鼠，肝胞浆中几乎检不到ＰＨＧ－Ｐｘ蛋白。ＰＨＧＰｘ活性降低与酶蛋白减少相平行。该酶在防止硒缺乏大鼠肝脏脂是过氧化物水平升高比经典的ＧＰｘ更重要。

Selenium deficiency and phospholipid hydroperoxide glutathione peroxidase in liver of rats

When weanling male rats of the Wistar fed a selenium-deficient diet ,the activity of selenium -glu- tathione peroxidase. (GPx ) decreased rapidly. Susceptibility of different GPx to selenium (Se) deficiency was in the following decreasing orders:liver cytosol classic GPx ,plasma GPx ,red blood cell GPx and liv- er cytosol phospholipid hydroperoxide CPx (PHGPx) . Cel - filtration chromatography showed that liver cytosol of rats was of GPx activity reducing dilinoleoyl phosphatidylcholine hydroperoxide (PCOOH ) other than PHGPx. Western blot analysis revealed that the amount of 22 - KDa protein detectable with anti - PHGPx antibody in liver cytosol of Se - deficient rats decreased in parallel with the decrease in PHGPx activity and that after 9 weeks of the feeding , this immunoreactive protein was almost unde- tectable. The PHGPx is much more crucial than clssic GPx in preventing the elevation of liver lipid per- oxides levels in Se -deficient rats.