Ong M L, Kellen J A, Malkin D G, Malkin A
Tumour Biol. 1986;7(2-3):105-13.
Generation of T3 and rT3 from T4 was studied in R3230AC mammary tumours grown in Fischer 344 rats as well as in the liver and kidney of these tumour-bearing hosts. The primary objective of this study was to determine if reversion of T3 to rT3 synthesis occurs in this experimental tumour model and in organs remote from the tumour site. Tumours, hepatic and renal homogenates were analyzed 14-16 days following tumour implantation for 5- and 5'-iodothyronine deiodinase activity using thyroxine as substrate. It was observed that similar to the liver and kidney, the mammary tumour was capable of generating both T3 and rT3 from T4; renal synthesis of T3 was significantly greater than that of rT3 in tumour hosts and controls. In contrast, there was no significant difference between T3 and rT3 synthesis in the tumour itself and the livers of normal and tumour-bearing animals. Hepatic and renal T3 synthesis were greater in the tumour-bearing than in the normal rats; no difference in the hepatic and renal rT3 synthesis was observed between the tumour-bearing and the normal animals. Despite the fact that serum T3 was significantly lower in the tumour-bearing than in the normal rats, no difference in the serum rT3 level was observed between the two groups of animals. Our data demonstrate that in this particular animal model there is no evidence of dedifferentiation of iodothyronine deiodinase activity either within the tumour or in remote tissues.
在Fischer 344大鼠体内生长的R3230AC乳腺肿瘤以及这些荷瘤宿主的肝脏和肾脏中，研究了从T4生成T3和反式T3（rT3）的过程。本研究的主要目的是确定在这个实验性肿瘤模型以及远离肿瘤部位的器官中，是否会发生T3合成向rT3合成的转变。在肿瘤植入后14 - 16天，使用甲状腺素作为底物，对肿瘤、肝脏和肾脏的匀浆进行5-和5'-碘甲状腺原氨酸脱碘酶活性分析。结果观察到，与肝脏和肾脏相似，乳腺肿瘤能够从T4生成T3和rT3；在肿瘤宿主和对照组中，肾脏T3的合成显著高于rT3。相比之下，肿瘤本身以及正常和荷瘤动物肝脏中T3和rT3的合成没有显著差异。荷瘤大鼠肝脏和肾脏中T3的合成高于正常大鼠；荷瘤动物和正常动物肝脏及肾脏中rT3的合成没有差异。尽管荷瘤大鼠血清T3显著低于正常大鼠，但两组动物血清rT3水平没有差异。我们的数据表明，在这个特定的动物模型中，无论是在肿瘤内部还是在远处组织，都没有证据表明碘甲状腺原氨酸脱碘酶活性去分化。
