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近年来,随着对甲状腺激素的研究不断深入,对甲状腺激素的生理生化及病理生理都有不少新的发现和认识。本文就甲状腺激素的外周过程和在各种疾病血中浓度的变化作以下概述。外周过程一、种类、来源及转运甲状腺合成并分泌释放进入血液循环中的甲状腺素,其中主要有3、5、3＇、5＇-L四碘甲状腺激素原氨酸[简称甲腺原氨酸(T_4)],还有少量3、5、3＇-L三碘甲腺原氨酸(T_3)和3、3＇、5＇-L三碘甲腺原氨酸(rT_3,即反T_3)。T_4和T_3具有生物活性,而rT_3则没有或很少有生物活性。血中T_4含量最大,全部来源于甲状腺。甲状腺每天分泌T_4约90μg。T_4在甲状腺外周池的总量约为900μg,每天周转率约为10％。血浆T_4浓度为5～12μg/dl,半衰期约7天。T_3有两个来源,30％来自于甲状腺,70％由T_4在外周脱碘生成。T_3每天生成量约为30μg,甲状腺外周池的总量约为40μg,每天周转率约为75％。血浆T_3浓度
In recent years, with the continuous research on thyroid hormone, there are many new discoveries and understandings on the physiological, biochemical and pathophysiology of thyroid hormone. This article summarizes the peripheral processes of thyroid hormones and the changes in blood concentrations in various diseases. Peripheral processes First, the type, source and transport of thyroid synthesis and secretion of thyroid hormone release into the blood circulation, which mainly 3,5,5 ’, 5’-L tetraiodothyronine [referred to as thyronine (T_4)], a small amount of 3,5,3’-L triiodothyronine (T_3) and 3,3 ’, 5’-L triiodothyronine (rT_3, ie anti-T_3) . T_4 and T_3 have biological activity, while rT_3 has little or no biological activity. T_4 blood maximum, all from the thyroid. Thyroid secretion T_4 about 90μg every day. The total amount of T_4 in the peripheral thyroid gland is about 900 μg and the daily turnover rate is about 10%. Plasma T_4 concentration of 5 ~ 12μg / dl, half-life of about 7 days. There are two sources of T_3, 30% from the thyroid and 70% from the peripheral deiodination of T_4. The amount of T_3 produced per day was about 30 μg, the total amount of thyroid peripheral pools was about 40 μg, and the daily turnover rate was about 75%. Plasma T_3 concentration