促甲状腺激素和三碘甲状腺原氨酸调节FRTL-5大鼠甲状腺细胞中碘甲状腺原氨酸5'-脱碘酶信使核糖核酸水平。

Thyrotropin and triiodothyronine regulate iodothyronine 5'-deiodinase messenger ribonucleic acid levels in FRTL-5 rat thyroid cells.

作者信息

Toyoda N, Nishikawa M, Mori Y, Gondou A, Ogawa Y, Yonemoto T, Yoshimura M, Masaki H, Inada M

机构信息

Second Department of Internal Medicine, Kansai Medical University, Osaka, Japan.

出版信息

Endocrinology. 1992 Jul;131(1):389-94. doi: 10.1210/endo.131.1.1319323.

DOI:10.1210/endo.131.1.1319323

PMID:1319323

Abstract

We investigated the regulation of type I iodothyronine 5'-deiodinase (5'-D) gene expression by TSH and T3 in FRTL-5 rat thyroid cells. Northern blot analysis revealed that these cells express a 5'-D messenger RNA (mRNA) species of 2.1 kilobases. Readdition of TSH to FRTL-5 cells, precultured in both thyroid hormones and TSH-depleted medium for 4 days, increased 5'-D mRNA levels, reaching a maximum (2.8-fold compared to control) after 12 h of TSH (10 microU/ml) stimulation. Dibutyryl cAMP (DBC) and forskolin mimicked this stimulatory effect of TSH on 5'-D mRNA levels. T3 also increased the 5'-D mRNA levels, reaching a maximum (2-fold compared to control) after 8 h of T3 (10(-9) M) stimulation. Addition of TSH (10 microU/ml) or DBC (1 mM) together with T3 (10(-9) M) further increased 5'-D mRNA levels, reaching a maximum (5-fold compared to control) after 12 h of stimulation. Examination of the rate of disappearance of 5'-D mRNA levels after inhibition of mRNA transcription by actinomycin-D revealed that neither TSH nor T3 significantly affected the rate of disappearance. Cycloheximide, a protein synthesis inhibitor, almost completely blocked the induction of 5'-D mRNA by TSH and DBC, but did not block the induction by T3. These results suggest that both TSH and T3 increase 5'-D mRNA levels probably by increasing transcription rate, and that TSH regulates it, in part via the second messenger cAMP, for which cycloheximide-sensitive de novo protein synthesis is required, whereas T3 does without requiring it.

摘要

我们研究了促甲状腺激素（TSH）和三碘甲状腺原氨酸（T3）对FRTL-5大鼠甲状腺细胞中I型碘甲状腺原氨酸5'-脱碘酶（5'-D）基因表达的调控。Northern印迹分析显示，这些细胞表达一种2.1千碱基的5'-D信使核糖核酸（mRNA）。将预先在甲状腺激素和TSH耗尽的培养基中培养4天的FRTL-5细胞重新添加TSH，可增加5'-D mRNA水平，在TSH（10微单位/毫升）刺激12小时后达到最大值（与对照相比增加2.8倍）。二丁酰环磷腺苷（DBC）和福斯可林模拟了TSH对5'-D mRNA水平的这种刺激作用。T3也增加了5'-D mRNA水平，在T3（10⁻⁹ M）刺激8小时后达到最大值（与对照相比增加2倍）。将TSH（10微单位/毫升）或DBC（1毫摩尔）与T3（10⁻⁹ M）一起添加可进一步增加5'-D mRNA水平，在刺激12小时后达到最大值（与对照相比增加5倍）。在用放线菌素-D抑制mRNA转录后，检测5'-D mRNA水平的消失速率，结果显示TSH和T3均未显著影响消失速率。蛋白质合成抑制剂环己酰亚胺几乎完全阻断了TSH和DBC对5'-D mRNA的诱导，但未阻断T3的诱导。这些结果表明，TSH和T3可能都通过增加转录速率来提高5'-D mRNA水平，并且TSH部分通过第二信使环磷腺苷来调节它，这需要环己酰亚胺敏感的从头蛋白质合成，而T3的调节则不需要。