Saturable binding of thyroid hormone to isolated rat hepatocytes

FEBS Letters

Blondeau, Jean-Paul¹ 

[1]Unité de Researches sur la Glande Thyroide et la Régulation Hormonale (U.96), Institut National de la Santé et de la Rsearch Médicale, 78, rue du Général Leclerc, 94275 Le Kremlin-Bicêtre Cedex, France

关键词: Triiodothyronine;    Thyroid hormone receptor;    Cell membrane binding site;    Thyroid hormone action;    Bromosulfophthalein;    (Isolated hepatocyte);   

DOI  :  10.1016/0014-5793(86)81384-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The binding of [¹²⁵I]triiodothyronine (T₃) to freshly prepared rat hepatocytes was studied at 0°C. The abundant non-saturable binding could be suppressed by washing the cells with alkaline buffer, pH 10.5 at 0° C, without loss of cell viability, thus allowing detection of saturable binding. Three classes of binding sites were indentified from analysis of the sautrable T₃ binding in the presence and absense of bromosulfophthalein (BSP). One of these classes was inhibited by BSP. The T₃ dissociation constants were 3.5, 35 and 115 nM and the number of sites was respectively 0.9, 20 and 36 × 10⁶ sites/cell. L-T₃ had a 10-times higher affinity than D-T₃ and a 50-times higher affinity than triiodothyroacetic acid. Saturable T₃ binding was associated with plasma membrane-containing subcellular fractions. These binding sites may be related to those previously described in isolated plasma membranes from rat liver and could be involved in the entry of T₃ into the hepatocyte.

【 授权许可】

Unknown