钙缺乏对克山病病区粮养大鼠肾脏Ⅰ型T_45′—脱碘酶活性的影响

EFFECT OF CALCIUM DEFICIENCY ON RENAL TYPE I IODOTHYRONINE 5'-DEIODINASE ACTIVITY IN THE RATS FED GRAINS FROM KESHAN DISEASE ENDEMIC AREA

以克山病病区玉米和黄豆为主,组成偏食低钙及补钙饲料喂养大鼠8周,结果病区粮所饲大鼠生长缓慢,血清总钙含量、肾脏Ⅰ型T_45′—脱碘酶(ID—I)活性、血清T_3浓度及全血和肾脏谷胱甘肽过氧化物酶(GSH—Px)活力显著降低,血清和肾脏脂质过氧化物(LPO)浓度增加。补钙使上述指标显著改善,恢复至常规饲料组水平。提示膳食低钙本身即可抑制ID—I活性,使甲状腺激素(TH)代谢发生障碍,机体抗氧化能力减退。膳食低钙可能参与了克山病发病中的TH代谢障碍过程。

Experimenting on the rats maintained on low calcium (Ca)and supplemented Ca diets mainly composed of maize and soybean from Keshan Disease (KD) endemic area for 8 weeks demonstrated that weight gain in the rats fed the endemic diet was slow, their renal type I iodothyro-nine 5' -deiodinase (ID-I) activity, serum T3 concentration and glutathione peroxidase (GSH-Px) activity in blood and kidney were strikingly lower than those in non-endemic and stock diet, the contents of lipid peroxides (LPO) in serum and kidney were remarkably increased. When the endemic diet was supplemented with Ca alone, the above-mentioned indexes were improved. These results suggested that dietary low Ca itself might, impair ID-I activity and thyroid hormone (TH) metabolism and organic antioxidative ability. Dietary low Ca might take part in the process of TH metabolic disturbance in the development of KD.