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[~(3)H I Cortisol及[~(3)H ] Dexamethasone 在大鼠肝细胞膜上的特异结合位点

周洁, 王大有, 刘鼎新

北京医科大学第三医院内分泌研究室 北京100083 北京医科大学细胞生物教研室 北京 100083

摘要

本研究应用[3Hj cortisol和[3H] dexamethasone (DEX)两种配基，观察到大鼠肝细胞膜上存在一类糖皮质激素(GC)特异结合位点。这些位点与GC的结合具有饱和性、高亲和力及低容量。其平衡解离常数(Kd)分别为12.84士6. 58 nmol/L和40: 27士23. 44 nmol/L;最大结合容量Borax)分别为2.57士1. 84 pmol/mg蛋白质与0.64士0. 18 pmol/mg蛋白质(cortisol, n=4; DEX,n=3;艾士SE)。动力学实验数据所得的Kd值与Scatchard分析所得的Kd值结果基本一致。['H] cortisol和[3H] DEX饱和结合实验数据用Scatchard作图分析，均显示为直线。Hill系数则分别为0. 9880和0. 9990。竞争抑制实验结果表明，cortisol对〔3H] cortisol的结合位点有高度特异性竞争，比其它几种类固醇(强的松、黄体酮、RU486, DEX)的竞争力至少强40倍以上。用放射自显影技术进行研究，也提供了「3H] cortisol特异结合银粒位于大鼠肝细胞膜上的依据。

关键词： 肝细胞膜; 结合位点; 糖皮质激素受体

SPECIFIC BINDING SITES OF [~(3)]CORTISOL AND 〔~(3)H] DEXAMETHASONE IN RAT LIVER CELL MEMBRANE

Cheng Zhiping

Department of Physiology harbin Medical University , harbin 150086

Abstract

By using[IH〕 cortisol and〔3H〕 dexamathasone (DEX)，a class of specific binding sites of glucocorticoids (GC) in rat liver cell membrane was observed. These binding sites had saturability，high affinity and low capacity. The kinetic parameters of [3H] cortisol and [3H〕 DEX were:Kd=12. 84士6. 58 nmol/L (n=4) and 40. 27士23. 44 nmol/L (n=3) respectively;Bmax=2.57士1. 84 pmol/mg protein and 0. 64士0. 18 pmol/mg protein respectively (X士SE).The Kd obtained from the kinetic studies was corresponding to the results.of Scatchard analysis. Scatchard plots from the equilibrium experiments showed the straight line. The Hill coefficients were 0. 9880 and 0. 9990 respectively. The competitive displacement experiments indicated that cortisol possessed the higher specificity for the [3H ] cortisol binding sites than other tested steroids (prednisolone，progesterone，RU486，DEX).The competitive ability of cortisol was at least 40 folds higher than mentioned steroids. By means of autoradiography technique，the existence of[3H〕 cortisol labelled particles on the liver cell membrane was found.

Key words: elucocorticoids ; liver cell membrane;

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引用本文：

周洁, 王大有, 刘鼎新. [~(3)H I Cortisol及[~(3)H ] Dexamethasone 在大鼠肝细胞膜上的特异结合位点[J]. 生理学报 1994; 46 (5): .

Cheng Zhiping. SPECIFIC BINDING SITES OF [~(3)]CORTISOL AND 〔~(3)H] DEXAMETHASONE IN RAT LIVER CELL MEMBRANE. Acta Physiol Sin 1994; 46 (5): (in Chinese with English abstract).