HEPATIC CLEARANCE OF APOLIPOPROTEIN B

富含甘油三酯的脂蛋白(TRL)的载脂蛋白B变异成分具有 对脂蛋白(LP)颗粒分解代谢命运的影响。虽然 载脂蛋白BH(高MR载脂蛋白B)和载脂蛋白BL(低MR载脂蛋白B)的差异 新陈代谢已有报道，其异质性的原因尚不清楚。 探索过了。受体介导的脂蛋白去除已经被广泛研究，并且 最近的证据表明载脂蛋白BL不与乳胶粒相互作用 (Cm)肝脏中残存受体途径。因此，异质性的原因 载脂蛋白B代谢可能发生在受体事件之前，是一种特性 粒子的数量。与兔子和人类不同的是，老鼠既有载脂蛋白B 肝脏合成TRL的变异体。脂肪酶对TrL的修饰 (脂蛋白脂肪酶和/或肝脂酶)在优先考虑之前是必需的 观察肝脏载脂蛋白的清除情况。决定LP的其他因素 包括载脂蛋白C组成、载脂蛋白C III：C II比率、载脂蛋白E含量、 甘油三酯与胆固醇酯含量、身体大小和代谢的关系 州政府。目前尚不清楚的是，这些事件如何在某种程度上改变LP结构 从而影响LP随后的分解代谢命运。假设是 检测的是观察到的含载脂蛋白B的脂蛋白的异质性代谢 与载脂蛋白B的表达有关，而载脂蛋白B的表达又受颗粒脂质的影响 和脱脂蛋白组成。低密度脂蛋白载脂蛋白B对肝脏清除率的研究 建议强调受体前事件(合成和脂解) 更改LP构图。对肝脏有利的载脂蛋白成分 脂多糖的清除将被确定，并将与肝脏有关 安全通道。我们已经研制出了针对大鼠的单抗 将用于分离独特型LPs亚群的载脂蛋白 分解代谢研究的表位组合物。其他单抗也将用于 对存在于LP上的构象表位的灵敏免疫分析 用于确定其他载脂蛋白B表位的两种位点分析方法的建立 以及颗粒上存在的载脂蛋白表位。拟议的实验将 继续研究载脂蛋白B在体内和肝脏灌流中的周转。模型 代谢环境的改变将包括链脲佐菌素 糖尿病、泛肾病和胆固醇喂养的大鼠，我们将延长 原代培养大鼠和兔肝细胞的分解代谢研究。粒子 载脂蛋白B脂蛋白的组成被认为是肝脏清除的关键。研究 认为载脂蛋白B-LP的关系是正的 动脉粥样硬化形成的危险因素。

Apo B variant composition of triglyceride-rich lipoproteins (TRL) has an influence on the catabolic fate of the lipoprotein (Lp) particle. Although differences in apo BH (higher Mr apo B) and apo BL (lower Mr apo B) metabolism have been reported, reasons for the heterogeneity remain to be explored. Receptor-mediated Lp removal has been studied extensively and recent evidence suggests that apo BL does not interact with the chylomicron (CM) remnant receptor pathway in the liver. Thus, reasons for heterogenous apo B metabolism probably occur prior to receptor events and are a property of particles. Rats, in contrast to rabbits and humans, have both apo B variants in hepatically synthesized TRL. TRL modification by lipases (lipoprotein lipase and/or hepatic lipase) is necessary before preferential hepatic apo BL clearance is observed. Other factors which determine Lp clearance include apo C composition, apo CIII:CII ratio, apo E content, triglyceride vs. cholesterol ester content, physical size, and metabolic state. What is not known is how these events alter Lp structure in a way as to affect the subsequent catabolic fate of the Lp. The hypothesis to be tested is that observed heterogeneous metabolism of apo B-containing Lps relates to apo B expression which in turn is influenced by particle lipid and apoprotein composition. Study of hepatic clearance of Lp apo B is proposed stressing pre-receptor events (synthetic and lipolytic) which alter Lp composition. Favorable apoprotein composition for hepatic clearance of Lps will be determined and will be related to hepatic clearance pathways. We have developed monoclonal antibodies (mAbs) to rat apoproteins which will be used to isolate subpopulations of Lps of unique epitope composition for catabolic studies. Other mAbs will also be used in sensitive immunoassays for conformational epitopes present on Lps to allow development of two site assays in order to determine other apo B epitopes and apoprotein epitopes present on particles. Proposed experiments will continue studies of apo B turnover in vivo and in liver perfusion. Models of altered metabolic circumstances will include the streptozotocin diabetic, PAN-nephrotic and cholesterol-fed rat and we will extend catabolic studies to primary rat and rabbit hepatocyte cultures. Particle composition of apo B Lps is seen as critical to hepatic clearance. Studies assume importance considering the relationship of apo B-Lps as positive risk factors in atherogenesis.