Fukasawa N
Fourth Department of Internal Medicine, Saitama Medical School.
Nihon Naibunpi Gakkai Zasshi. 1991 Oct 20;67(10):1178-85. doi: 10.1507/endocrine1927.67.10_1178.
BioBreeding/Worcester (BB/W) rats develop insulin dependent diabetes mellitus (IDDM) and lymphocytic thyroiditis (LT) spontaneously. Our previous studies have shown that BB/W (Saitama-Tokyo colony) rats develop LT at about 10 weeks of age. Their serum TSH values increase as LT extends, although their serum thyroid hormone levels remain normal. This indicates that BB/W rats suffer from subclinical hypothyroidism. To investigate whether BB/W rats have a defect in iodide metabolism, the thyroidal radioactive iodine uptake (RAIU) in BB/W rats was examined. Thyroidal RAIU at 3hr in both 8 and 16 week-old BB/W rats was significantly higher than that in age-matched normal Wistar rats. On the other hand, BB/W rats had significantly lower 48hr thyroidal RAIU than normal Wistar rats. This suggests that BB/W rats appear to have some defects in iodide metabolism, especially in iodide organification even before the development of LT. The expression of thyroid peroxidase (TPO) and thyroglobulin (Tg) mRNA in BB/W and Wistar rats was then examined using the Northern blot analysis. The expression of both TPO and Tg mRNA was greatly decreased in BB/W rats compared with that in Wistar rats despite the high serum TSH levels in BB/W rats. This indicates that BB/W rats may have pretranslational defects in TPO and Tg synthesis, resulting in the impaired thyroid hormone synthesis. In the present study, it has been demonstrated that BB/W rats appear to have a defect(s) in iodide metabolism possibly due to some abnormalities in TPO and Tg synthesis.
BioBreeding/伍斯特（BB/W）大鼠会自发发展为胰岛素依赖型糖尿病（IDDM）和淋巴细胞性甲状腺炎（LT）。我们之前的研究表明，BB/W（埼玉-东京品系）大鼠在约10周龄时会患上LT。随着LT的发展，它们的血清促甲状腺激素（TSH）值会升高，尽管其血清甲状腺激素水平仍保持正常。这表明BB/W大鼠患有亚临床甲状腺功能减退症。为了研究BB/W大鼠是否存在碘代谢缺陷，我们检测了BB/W大鼠的甲状腺放射性碘摄取（RAIU）情况。8周龄和16周龄的BB/W大鼠在3小时时的甲状腺RAIU均显著高于年龄匹配的正常Wistar大鼠。另一方面，BB/W大鼠48小时的甲状腺RAIU显著低于正常Wistar大鼠。这表明BB/W大鼠似乎在碘代谢方面存在一些缺陷，尤其是在LT发生之前的碘有机化过程中。随后，我们使用Northern印迹分析检测了BB/W大鼠和Wistar大鼠中甲状腺过氧化物酶（TPO）和甲状腺球蛋白（Tg）mRNA的表达。尽管BB/W大鼠血清TSH水平较高，但与Wistar大鼠相比，BB/W大鼠中TPO和Tg mRNA的表达均大幅降低。这表明BB/W大鼠在TPO和Tg合成方面可能存在转录前缺陷，导致甲状腺激素合成受损。在本研究中，已证明BB/W大鼠似乎存在碘代谢缺陷，这可能是由于TPO和Tg合成中的某些异常所致。
