Dresel H A, Friedrich E, Via D P, Schettler G, Sinn H
EMBO J. 1985 May;4(5):1157-62. doi: 10.1002/j.1460-2075.1985.tb03754.x.
Acetylated low density lipoprotein (acetyl-LDL) binding to hepatic membrane proteins of rats was analysed in vitro by ligand blotting. Specific binding could be demonstrated to two hepatic proteins with an apparent mol. wt. of 250 kd and 220 kd. Polyanionic competitors and maleylated bovine serum albumin inhibited the binding of acetyl-LDL effectively. To determine the sites of the catabolism of acetyl-LDL, [131I]-acetyl-LDL was injected intravenously into control rats and rats pre-treated with the known competitors of the acetyl-LDL binding. Distribution of the radiolabelled acetyl-LDL was followed by a scintillation camera. Six minutes after injection, the radioactivity was concentrated in the liver. The competitors and unlabelled acetyl-LDL but not native LDL reduced the hepatic uptake of [131I]acetyl-LDL dramatically. Thus, the sensitivity of the 220- and 250-kd membrane binding sites to the competitors for the acetyl-LDL binding resembled that of the hepatic compartment in vivo. Finally, an application of scintigraphy with radiolabelled low density lipoproteins for diagnostic evaluation of tumor compartments is presented.
通过配体印迹法在体外分析了乙酰化低密度脂蛋白（acetyl-LDL）与大鼠肝细胞膜蛋白的结合情况。可证明其与两种肝蛋白存在特异性结合，这两种蛋白的表观分子量分别为250kd和220kd。聚阴离子竞争剂和马来酰化牛血清白蛋白可有效抑制乙酰-LDL的结合。为确定乙酰-LDL的分解代谢位点，将[131I]-乙酰-LDL静脉注射到对照大鼠和预先用已知的乙酰-LDL结合竞争剂处理过的大鼠体内。用闪烁相机追踪放射性标记的乙酰-LDL的分布情况。注射后6分钟，放射性集中在肝脏。竞争剂和未标记的乙酰-LDL可显著降低肝脏对[131I]乙酰-LDL的摄取，但天然LDL则无此作用。因此，220kd和250kd膜结合位点对乙酰-LDL结合竞争剂的敏感性与体内肝脏区域的敏感性相似。最后，介绍了放射性标记低密度脂蛋白闪烁显像在肿瘤区域诊断评估中的应用。
