EFFECTS OF LOW IODINE FEEDING ON T_4 5'-DEIODINASE ACTIVITY IN BRAIN TISSUE OF NEWBORN RATS
- VernacularTitle:低碘饲养对大鼠仔鼠脑组织T_45′-脱碘酶活性的影响
- Author:
Jiayi WANG
- Publication Type:Journal Article
- Keywords:
Thyroxine 5'-deiodinase 3,5,3'-triiodothyronine Thyroid hormone Hypothyroidism
- From:
Chinese Journal of Endocrinology and Metabolism
1985;0(01):-
- CountryChina
- Language:Chinese
-
Abstract:
Female rats were divided into three groups: 1) LI group, receiving low iodine diet and distilled water; 2) NI group being fed with the same food as LI group and distilled water supplemented with potassium iodide; and 3) N group,taking usual diet and tap water. T4 5'-deiodinase, T, and T4 content in whole brain homogenate and serum T, and T4 level of the young animals delivered by the above-mentioned rats were analyzed. Deiodinase activity was expressed in terms'of T3→T4 conversion rate (CR). The results showed that the average CR in rat brain homogenates of LI group was significantly higher than those of the other two groups, it is 2.73 times of that in N group. There were no significant differences among the three groups in serum T3 concentration and T3 content of brain homogenate. But serum T4 concentration of LI group was only 10.9% of that in N group and brain homogenate T4 level was also lower, being only 38.5% of the latter. It suggested that T4 5'-deiodinase in the immature rat brain is more effective than in adult one on modulating thyroid hormone function in brain. Thus, the increased activity of brain T4 5'-deiodinase may compensate for the decreased T4 pool, maintaining a normal brain T3 content in congenital iodine-deficient rat.
