NUCLEAR THYROID-HORMONE RECEPTORS IN CULTURED BONE-CELLS
NUCLEAR THYROID-HORMONE RECEPTORS IN CULTURED BONE-CELLS
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DOI：
10.1016/0026-0495(86)90098-3
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发表时间：
1986-01-01
影响因子：
9.8
通讯作者：
BURGI, U
中科院分区：
文献类型：
--
作者：
RIZZOLI, R;POSER, J;BURGI, U
甲状腺激素影响骨代谢，但三碘甲状腺原氨酸与骨细胞核T3受体的直接相互作用尚未报道。我们研究了125 I-T3结合克隆成骨细胞样大鼠骨肉瘤细胞ROS 17/2.8分离的细胞核。在37度。C，饱和125 I-T3结合到分离的细胞核达到平衡的30分钟，并完全取代后，加入500 nmol/L的未标记的T3。非饱和结合约占添加放射性的0.5%（总结合的20%）。甲状腺素和3，3“，5”三碘甲状腺原氨酸与125 I-T3竞争，亲和力分别比T3低20倍和400倍。平衡竞争实验的分析揭示了存在单一类别的均质结合位点，其结合常数为5.0 ± 0.5。0.3. times. 109 mol/L-1，最大核结合容量为0.13 ± 0.15。0.02 ng/mg DNA。用T3处理观察到骨Gla蛋白（BGP）分泌的两倍增加，表明这些T3核受体与生物反应偶联。
Thyroid hormones influence bone metabolism, but a direct interaction of triiodothyronine with nuclear T3 receptors in bone cells has not yet been reported. We investigated 125I-T3 binding to nuclei isolated from the cloned osteoblastlike rat osteosarcoma cells ROS 17/2.8. At 37.degree. C, saturable 125I-T3 binding to isolated nuclei reached equilibrium by 30 minutes and was completely displaced upon the addition of 500 nmol/L unlabeled T3. Nonsaturable binding represented about 0.5% of the radioactivity added (20% of the total binding). Thyroxine and 3,3'',5''triiodothyronine competed with 125I-T3 with a 20-fold and 400-fold lower affinity than T3, respectively. Analysis of equilibrium competition experiments revealed the presence of a single class of homogeneous binding sites with an association constant of 5.0 .+-. 0.3 .times. 109 mol/L-1 and a maximum nuclear binding capacity of 0.13 .+-. 0.02 ng/mg DNA. A twofold increase of bone Gla protein (BGP) secretion was observed with T3 treatment suggesting that these T3 nuclear receptors are coupled with a biological response.