Knight B L, Soutar A K, Patel D D
Atherosclerosis. 1987 Apr;64(2-3):131-8. doi: 10.1016/0021-9150(87)90238-3.
In monocyte-derived macrophages from both normal and familial hypercholesterolaemic (FH) subjects, degradation of low density lipoprotein (LDL) through non-saturable pathways produced the same fall in 3-hydroxy-3-methylglutaryl-CoA reductase activity as receptor-mediated degradation of acetylated LDL, yet did not lead to as great an increase in incorporation of [14C]oleate into cholesteryl esters. Studies using FH cells showed that the simultaneous addition of LDL did not reduce oleate incorporation resulting from degradation of acetylated LDL, and that there was a similar relationship for both lipoproteins between the increase in net oleate incorporation and the increase in the cholesteryl ester content of the cells. FH cells maintained in serum-free medium accumulated more free cholesterol than cells in lipoprotein-deficient serum when incubated with LDL but not when incubated with acetylated LDL. The results suggest that the cholesterol released from non-saturable degradation of LDL is more easily removed from the cells by acceptors in the medium than cholesterol released from receptor-mediated uptake of acetylated LDL, and is not readily available for esterification.
在来自正常受试者和家族性高胆固醇血症（FH）患者的单核细胞衍生巨噬细胞中，低密度脂蛋白（LDL）通过非饱和途径降解导致3-羟基-3-甲基戊二酰辅酶A还原酶活性下降的幅度，与乙酰化LDL的受体介导降解相同，但并未导致[14C]油酸酯掺入胆固醇酯的增加幅度同样大。使用FH细胞的研究表明，同时添加LDL并不会降低乙酰化LDL降解导致的油酸酯掺入，并且两种脂蛋白在净油酸酯掺入增加与细胞胆固醇酯含量增加之间存在相似关系。在无血清培养基中培养的FH细胞，与LDL孵育时比与脂蛋白缺乏血清中的细胞积累更多游离胆固醇，但与乙酰化LDL孵育时则不然。结果表明，LDL非饱和降解释放的胆固醇比受体介导摄取乙酰化LDL释放的胆固醇更容易被培养基中的受体从细胞中清除，并且不易用于酯化。
