EVALUATION IN-VIVO OF THE DIFFERENTIAL UPTAKE AND PROCESSING OF HIGH-DENSITY-LIPOPROTEIN UNESTERIFIED CHOLESTEROL AND CHOLESTERYL ESTER IN THE RAT
EVALUATION IN-VIVO OF THE DIFFERENTIAL UPTAKE AND PROCESSING OF HIGH-DENSITY-LIPOPROTEIN UNESTERIFIED CHOLESTEROL AND CHOLESTERYL ESTER IN THE RAT
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DOI：
10.1016/0005-2760(94)90096-5
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发表时间：
1994-11-17
期刊：
影响因子：
--
通讯作者：
CANTAFORA, A
中科院分区：
文献类型：
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作者：
BRAVO, E;BOTHAM, KM;CANTAFORA, A
比较了大鼠体内高密度脂蛋白（HDL）未酯化和酯化胆固醇的摄取和加工情况。以未酯化胆固醇或胆固醇酯标记H-3的高密度脂蛋白（HDL）静脉注射，每隔180分钟研究血液中放射性的清除、其在血浆脂蛋白密度分数中的分布、组织的摄取和胆汁的外观。HDL未酯化胆固醇中的H-3比HDL胆固醇酯中的H-3从血液中清除得更快，这一差异主要是由于肝脏对[H-3]未酯化胆固醇的快速隔离，10分钟后肝脏中发现58.2%的给药剂量，而[H-3]胆固醇酯的给药剂量为6.8%。非肝组织仅从HDL未酯化和酯化胆固醇中摄取了一小部分给药标签，但在每克湿重的基础上，肾上腺和脾脏对HDL胆固醇酯的特定摄取高于肝脏，特别是在前60分钟。当使用[H-3]未酯化胆固醇时，血浆脂蛋白密度组分的放射性分布在10 ~ 180 min之间保持不变，但在极低密度脂蛋白（VLDL）组分中，标记为酯化胆固醇的HDL的血浆放射性比例从0%增加到26%，而在HDL中，放射性分布从密度最大的亚组分（d 1.125 ~ 1.250 g/ml）向密度最小的亚组分（d 1.050 ~ 1.085 g/ml）转变。在180分钟内，高密度脂蛋白未酯化胆固醇的比例（8.8%）高于高密度脂蛋白胆固醇酯（3.3%），但胆汁酸和未酯化胆固醇的比例在两种标签下相似。这些发现表明，在体内大鼠体内，与酯化胆固醇相比，未酯化HDL的摄取和加工有显著差异。
The uptake and processing of high-density lipoprotein (HDL) unesterified and esterified cholesterol were compared in vivo in the rat. HDL labelled with H-3 in either unesterified cholesterol or cholesteryl ester was administered intravenously, and the clearance of radioactivity from the blood, its distribution in plasma lipoprotein density fractions, uptake by tissues, and appearance in bile were studied at intervals up to 180 min. H-3 in HDL unesterified cholesterol was cleared more rapidly from the blood than that in HDL cholesteryl ester, and this difference was mainly due to rapid sequestration of [H-3]unesterified cholesterol by the liver, with 58.2% of the administered dose found in this tissue after 10 min, compared to 6.8% of the [H-3]cholesteryl ester dose. Non-hepatic tissues took up only a small proportion of the administered label from both HDL unesterified and esterified cholesterol, but on a per gram wet weight basis, the specific uptake of HDL cholesteryl ester in the adrenal glands and the spleen was higher than in the liver, particularly in the first 60 min. The distribution of radioactivity in the plasma lipoprotein density fractions remained constant between 10 and 180 min when [H-3]unesterified cholesterol was used, but the proportion of plasma radioactivity from HDL labelled in esterified cholesterol in the very-low-density lipoprotein (VLDL) fraction increased from O% to 26%, while in HDL there was a shift in the distribution of radioactivity from the most (d 1.125-1.250 g/ml) to the least (d 1.050-1.085 g/ml) dense sub-fractions. A greater percentage of the administered label from HDL unesterified cholesterol (8.8%) than from HDL cholesteryl ester (3.3%) was secreted into bile during 180 min, but the proportions secreted in bile acids and unesterified cholesterol were similar with both labels. These findings indicate that there are significant differences in the uptake and processing of HDL unesterified as compared to esterified cholesterol in the rat in vivo.