大鼠硒耗竭过程中不同组织硒蛋白利用硒的优先性

Priority of selenium incorporation into selenoproteins during selenium depletion in rats

以低硒酵母配制的低硒基础饲料（含硒量为０．０１ｍｇ／ｋｇ）和在此基础上加亚硒酸钠配成硒水平为０．５０ｍｇ／ｋｇ的足硒饲料来喂养雄性Ｗｉｓｔａｒ断乳大鼠。于０、１、２、４、６、８、１２、１５、１７、１９、２０和２４周时处死大鼠取其组织，分别对各种组织中的硒、细胞内谷胱甘肽过氧化物酶（ｃＧＰＸ）、细胞外谷胱甘肽过氧化物酶（ｅＧＰＸ）、磷脂氢谷胱甘肽过氧化物酶（ＰＨＧＰＸ）、Ⅰ型脱碘酶（ＩＤⅠ）和Ⅱ型脱碘酶（ＩＤⅡ）活性进行动态观察。结果发现睾丸中的硒和脑垂体中的ｃＧＰＸ在耗竭过程中降低速度较其它组织慢，且降低幅度较小；而硒蛋白中ＩＤⅠ和ＰＨＧＰＸ对硒的利用优先于ｃＧＰＸ和ｅＧＰＸ，ＰＨＧＰＸ和ＩＤⅠ的功能可能比ｃＧＰＸ和ｅＧＰＸ更重要。

Male weanling Wistar rats were fed with either a basal selenium deficient diet (a Torula yeast based semisynthetic diet, containing Se 0 01 mg/kg) or a selenium sufficient diet supplemented with Se as Na 2SeO 3 (containing Se 0 5mg/kg). Rats were killed after different weeks(0,1,2,4,8,12,15,17,19,20 and 24 respectively). Their organs were taken to observe the kinetic change of selenium concentration, the activities of intracellular glutathione peroxidase (cGPX),extracellular glutathione peroxidase(eGPX), and phospholipid hydroperoxide glutathione peroxidase (PHGPX) in different organs. The results showed that selenium levels and the activities of selenoenzyme in testis and pituitary were more resistant to selenium deficiency than other organs. During selenium deficiency, the utilization of selenium by PHGPX and deiodinase was prior to eGPX and cGPX, which suggested that the function of PHGPX and deiodinase were more important than that of eGPX and cGPX.