微量组织中低密度脂蛋白受体测定方法的建立及初步应用

DEVELOPMENT OF METHOD FOR THE DETERMINATION OF LOW DENSITY LIPOPROTEIN RECEPTORS IN LITTLE TISSUES AND ITS PRIMARY APPLICATION

报道了一种快速测定微量组织中低密度脂蛋白受体（ＬＤＬＲ）的简便方法，利用微孔滤膜（０．４５μｍ，２５ｍｍ）分离游离和结合的配基．实验表明：（１２５）Ｉ－ＬＤＬ与组织中ＬＤＬＲ的结合与（１２５）Ｉ－ＬＤＬ与生理细胞表面ＬＤＬＲ的结合具有相同的特性，即可饱和性、可竞争性及热敏感性．该方法仅需０．２ｇ组织，结合反应采用０℃温育４ｈ．用建立的方法测定了不同饮食对金黄地鼠肝组织中ＬＤＬＲ的影响，发现饮食胆固醇使金黄地鼠肝ＬＤＬＲ数目显著降低，多不饱和脂肪酸使ＬＤＬＲ数目明显升高，不同饮食对平均亲和力无明显影响．

A convenient binding assay has been developed for the determination of low density lipoprotein (LDL) receptors in little tissues. Tissue homogenates were incubated with￣(125)I-LDL and the ligand bound to the homogenate particles was separated from the unbound ligand by fitration. The assay developed should be of value in determining the number of LDL receptors in little tissue,since it is far less time-consuming and requires less material(0. 2g)than currently available methods. We use this new assay to determine the effect of various dietary on the hepatic LDL receptors in Golden hamsters,it was found that the number of LDL receptors was decreased by dietary cholesterol and increased significantly by dietary polyunsaturated fatty acids,while various dietary has no obvious effect on the affinity of￣(125)I-LDL bindig to LDL receptors.