低硒低维生素E人工饲料喂养大鼠甲状腺激素代谢的变化

Changes of thyroid hormone metabolism in Wistar rats fed with the artificial semisynthetic forage of low selenium and low Vitamin E

用低硒、低 VE 的人工半合成料饲养大鼠8周,引起甲状腺激素(TH)和自由基代谢紊乱(与补硒补 VE 鼠比较):1.肝、肾 T_45′-脱碘酶(ID-I)活性分别降低60%和50%,血清 T_3减少36%,T_4增加32%。联合补 VE 和硒肝 ID-I 活性和血清 T_3浓度较单纯补硒组显著增加。2.全血和肝脏 GSH-Px 活力分别降低70%和82%,血清和肝脏 LPO 浓度分别增加53%和40%。硒含量相同时,变更 VE 量对 GSH-Px 无明显影响。对于降低 LPO 浓度单纯补硒或 VE 不如联合补硒和 VE 效果好。提示 GSH-Px 活力主要受硒水平影响,而 ID-I 活力除受硒水平影响外,VE 对其有保护作用。其机制与 VE 的抗氧化作用从而保护 ID-I 存在部位微粒体膜的稳定性使之免遭自由基损伤及 VE 和硒的协同和相互节约作用有关。

These metabolic disorders of thyroid hormone(TH)and free radicals were observed in Wistar rats maintained on low selenium(Se)respectively and vitamin E(VE)artificial semisynthetic diet for 8 weeks(compared with Se and VE supplement rats):1.Hepatic and renal type I iodothyronine 5′-deiodi- nase(ID-I)activities decreased 60% and 50% serum T_3 reduced 36%,and T_4 increased 32%.Hepatic ID-I activty and serum T_3 concentration in Se and VE supplement group were markedly higher than those in Se supplement group.2.GSH-Px activities in whole blood and liver decreased 70% and 82% re- spectively.LPO concentrations in serum and liver increased 53% and 40%,respectively.When Se con- tent was identical,changes of VE content didn't markedly effect on GSH-Px activity,but the united sup- plement of Se and VE decreased remarkably LPO concentration.These data suggested that GSH-Px ac- tivity mainly was influenced by Se level,but ID-I activity was influenced by VE level in addition to Se level.VE played an protective role on ID-I and these mechanisms were related to that VE protects the stability of microsome membrane of existent region of ID-I from free radicals in iury as well as the coor- dinated action and mutual save of Se and VE.