Dissociation of beta-hydroxy-beta-methylglutaryl-CoA reductase activity from the overall rate of cholesterol synthesis in the liver following the intravenous administration of lipid.
Dissociation of beta-hydroxy-beta-methylglutaryl-CoA reductase activity from the overall rate of cholesterol synthesis in the liver following the intravenous administration of lipid.
复制标题
静脉注射脂质后，β-羟基-β-甲基戊二酰辅酶A还原酶活性与肝脏胆固醇合成总体速率的分离。
DOI：
10.1016/s0021-9258(19)69909-6
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发表时间：
1976
期刊：
影响因子：
--
通讯作者：
J. Dietschy
中科院分区：
文献类型：
--
作者：
F. Nervi;M. Carrella;J. Dietschy
给完整大鼠静脉注射肠脂蛋白或人造脂肪乳剂中携带的甘油三酯后，体外测定的肝脏中微粒体β-羟基-β-甲基戊二酰辅酶A还原酶活性显着升高。这种酶活性的升高与大鼠肝脏切片中胆固醇合成总速率的相应变化无关，通过将[3H]水或[1-14C]辛酸掺入不皂化脂质或毛地黄皂苷可沉淀甾醇中来测量。羟甲基戊二酰辅酶A还原酶活性与胆固醇合成总速率的解离程度与给予动物的脂质量、循环脂质水平以及肝细胞中表现的酮合成水平密切相关，表明这种现象可能是细胞脂肪酸水平升高的去垢作用的结果。无论如何，在这些实验环境下，羟甲基戊二酰辅酶A还原酶活性不再反映肝细胞合成胆固醇的速率。
After the intravenous administration to the intact rat of triglyceride carried in either intestinal lipoproteins or in an artificial fat emulsion, the enzymatic activities of microsomal beta-hydroxy-beta-methylglutaryl-CoA reductase activity in the liver assayed in vitro became markedly elevated. This elevation of enzyme activity was not associated with a corresponding change in the overall rate of cholesterol synthesis in the rat liver slice as measured by the incorporation of either [3H]water or [1-14C]octanoate into nonsaponifiable lipids or into digitonin-precipitable sterols. The degree of dissociation of hydroxymethylglutaryl-CoA reductase activity from the overall rate of cholesterol synthesis correlated closely with the amount of lipid administered to the animal, the level of circulating lipids, and the level of ketone synthesis manifest in the liver cell suggesting that this phenomenon might be the consequence of a detergent effect of elevated cellular levels of fatty acids. In any event, under these experimental circumstances hydroxymethylglutaryl-CoA redutase activity no longer reflects the rate at which the liver cell is synthesizing cholesterol.