自主性甲状腺腺瘤中甲状腺素 T4 向 T3 的转化率增加：从甲状腺功能正常到甲状腺毒症。

Increased thyroidal T4 to T3 conversion in autonomously functioning thyroid adenoma: from euthyroidism to thyrotoxicosis.

机构信息

Department of Endocrinology, Sisters of Mercy University Hospital Center, University of Zagreb, School of Medicine, Vinogradska , Croatia.

出版信息

Ann Endocrinol (Paris). 2011 Jun;72(3):208-10. doi: 10.1016/j.ando.2011.04.008.

DOI:10.1016/j.ando.2011.04.008

PMID:21640977

Abstract

AIM

The aim was to investigate whether the intrathyroid conversion of T4 to T3 in autonomously functioning thyroid adenoma (AFTA) tissue could influence serum T3 levels and suppression of TSH, especially in patients with borderline thyroid function.

PATIENTS AND METHODS

In ten patients with AFTA, thyroidal conversion of T4 to T3 was investigated in nodular and paranodular, TSH-suppressed tissue. All patients had normal serum T4 and suppressed TSH. Serum T3 was normal in six, and borderline or slightly increased in four. AFTA and paranodular tissues were surgically removed and frozen at -70°C, then homogenized in a glass homogenizer, centrifuged at 100,000×g, and particulate fraction collected as a pellet. Analysis mixture consisted of thyroid enzyme suspension in 50 μmol/L TRIS buffer with 5 μmol DTT and 200 μL 1.3 μmol T4. Incubation was performed at 37°C and the generation of T3 measured after 5, 10, 20 and 40 minutes respectively.

RESULTS

T3 production (pmol/mg protein) was significantly higher in AFTA than in paranodular tissues (8.8 1.2/Mean ± SE/vs. 1.8 ± 0.2; p<0.01), and excessively high (9.8, 14.1, 14.2 and 15.0) in four patients with borderline or slightly supranormal serum T3. A significant correlation was found between serum T3 concentrations and T3 generation (T4 conversion) in AFTA tissues.

CONCLUSION

Results suggest that increased thyroidal T4 to T3 conversion in AFTA tissue could be involved in an increased delivery of T3, increased serum T3 and suppressed serum TSH, particularly in patients with the disease evolving from euthyroid to an early hyperthyroid phase.

摘要

目的

研究自主性甲状腺腺瘤（AFTA）组织中 T4 向 T3 的甲状腺内转化是否会影响血清 T3 水平和 TSH 的抑制，特别是在甲状腺功能边缘状态的患者中。

方法

在 10 例 AFTA 患者中，研究了结节内和结节旁、TSH 抑制的组织中 T4 向 T3 的甲状腺内转化。所有患者的血清 T4 正常，TSH 抑制。6 例患者的血清 T3 正常，4 例患者的血清 T3 边缘或轻度升高。手术切除并将 AFTA 和结节旁组织在-70°C 下冷冻，然后在玻璃匀浆器中匀浆，以 100,000×g 离心，收集颗粒部分作为沉淀。分析混合物由甲状腺酶混悬液在 50 μmol/L TRIS 缓冲液中组成，含 5 μmol DTT 和 200 μL 1.3 μmol T4。孵育在 37°C 下进行，分别在 5、10、20 和 40 分钟后测量 T3 的生成。

结果

AFTA 组织中的 T3 生成（pmol/mg 蛋白）明显高于结节旁组织（8.8 1.2/Mean ± SE/与 1.8 ± 0.2；p<0.01），并且在 4 例血清 T3 边缘或轻度升高的患者中过高（9.8、14.1、14.2 和 15.0）。在 AFTA 组织中发现血清 T3 浓度与 T3 生成（T4 转化）之间存在显著相关性。