2001•Zhonghua neifenmi daixie zazhiRequires access
Thyroid function and expressions of thyroglobulin and thyroid peroxidase mRNA in rats at different iodine intake levels
Chen Zu-pei
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Abstract
Objective To study the effects of different iodine intake levels on thyroid function at gene expression level in rats. Methods Wistar rats were divided into normal iodine (NI), lower iodine (LI) and higher iodine groups (HI). The urinary iodine excretion, T 4 and T 3 of serum and thyroid tissue were measured, the expressions of thyroglobulin (TG) and thyroid peroxidase (TPO) mRNA in thyroid were determined by RT PCR. Results In LI group, the urinary iodine excretion, T 4, T 3 of serum and thyroid tissue were lower, the expression of TPO mRNA increased markedly, while TG mRNA decreased significantly. In HI group, T 4 showed a decreasing tendency in serum and was markedly reduced in thyroid tissue, along with significantly higher urinary iodine excretion and decreased expressions of TPO mRNA and TG mRNA. Conclusion Lower iodine intake for long term results in severe hypothyroidism, and compensatory increase of TPO mRNA expression but decrease of TG mRNA expression; higher iodine intake inhibits the expressions of both TPO、 TG mRNA as well as thyroid hormone synthesis, which in turn acts as a protective mechanism against iodine excess.