锌对甲状腺功能低下大鼠肝细胞核T_3受体的影响

Influence of zinc on liver nuclear T_3 receptors of hypothyroidism rats

目的探讨补锌对甲状腺功能低下大鼠肝细胞核T3受体特性的影响。方法用低碘饲料喂养诱导大鼠甲状腺功能低下,采用T3和离体肝细胞核结合实验方法,观察补锌对甲状腺功能低下大鼠肝细胞核T3受体的影响。结果甲状腺功能低下大鼠肝细胞核T3受体的亲合常数(Ka)增加(P<0.01),最大结合容量(MBC)明显下降(P<0.01)。补锌后血清T3、T4水平未见明显改变(P>0.05),肝细胞核T3受体的Ka值降低(P<0.05),MBC增加(P<0.05),T3受体占位率无明显改变(P>0.05)。结论补锌可通过调节肝细胞核T3受体的结合容量改善甲状腺功能低下大鼠的甲状腺功能。

Objective To observe the effects of zinc （Zn） on the character of liver nuclear T3 receptors in hypothyroid rats. Methods Wistar rats with iodine deficiency were duplicated by feeding low iodine food produced in iodine deficiency disorder areas, zinc was then given in different groups. Changes in the liver nuclear T3 receptors were observed by binding T3 into isolated liver cell nuclear. Results The occupant of T3 receptors did not change in all of the groups （P 〉 0.05）. In the hypothyroid rats, the affinity constant （Ka） of liver nuclear T3 receptors increased（P 〈 0.01 ）, while the maximal binding capacity （MBC） decreased（P 〈 0.01 ）. In the hypothyroid rats given Zn, although the serum T3,T4 concentration remained the same （P 〉 0.05）, the Ka of liver nuclear T3 receptors decreased （P 〈 0.05）, the MBC increased （P 〈 0.05）. Conclusions Zn supplementation could regulate the MBC of nuclear T3 receptors to improve the function of thyroid of hypothyroidism rats.