国家自然科学基金资助项目(39870298).
This work was supported by a grant from The National Natural Sciences Foundation of China (39870298).
为寻求一种可替代人肝细胞研究载脂蛋白(apolipoprotein, apo)CⅢ受体的生理模型,并探讨apoCⅢ受体的生理功能及其在内源性高甘油三酯血症发病机制中的作用,首先以125I标记的人apoCⅢ为配体,利用放射性配体结合分析法观察了人肝癌细胞系HepG2细胞是否有apoCⅢ受体存在.结果证实HepG2细胞上存在高亲和力的、可饱和的、特异的apoCⅢ受体结合位点,其受体的亲和力(Kd)和apoCⅢ受体结合容量(Bmax)分别为(9.53±1.03)×10-9 mol/L和(3.28±0.31) μg/g.随后又分别研究了胰岛素及胰高血糖素对HepG2细胞apoCⅢ受体功能的影响,结果表明:胰岛素可使HepG2细胞apoCⅢ受体结合容量(Bmax)显著增加,但对受体的亲和力(Kd)无影响;胰高血糖素可使HepG2细胞apoCⅢ受体亲和力显著下降(即Kd值升高),对受体的结合容量无影响.提示人肝apoCⅢ受体的功能可能受胰岛素及胰高血糖素的不同调节.
In order to develop an alternative and reliable model for further study of human hepatic apolipoprotein CⅢ receptor, and to elucidate the physiological function and regulation of apoCⅢ receptor, whether or not there were apoCⅢ receptors of HepG2 cells by radioligand binding assay was first studied. Addition of increasing concentration of 125I-apoCⅢ to HepG2 cells revealed a saturable binding to HepG2 cells with a Kd of (9.53±1.03)×10-9 mol/L. The maximum specific binding capacity (Bmax) was (3.28±0.31) μg/g. The results showed that there were specific, saturable, and reversible binding site of apoCⅢ on HepG2 cells, and it was identified that HepG2 cell line was a useful model for the study of human hepatic apoCⅢ receptor. In the following, the effects of insulin and glucagon on apoCⅢ receptr of HepG2 cells were examined respectively. The results showed that insulin had no effect on the Kd value, but significantly increased the Bmax value of apoCⅢ receptor; and glucagon had no effect on the Bmax, but decreased the affinity constant of apoCⅢ receptor. These results indicated that human hepatic apoCⅢ receptor was possibliy under the different regulations of insulin and glucagon.
刘皓,刘秉文,李强.胰岛素及胰高血糖素对HepG2细胞载脂蛋白CⅢ受体功能的影响[J].生物化学与生物物理进展,2003,30(4):594-598
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