Stearic acid modifies very low density lipoprotein lipid composition and particle size differently from shorter-chain saturated fatty acids in cultured rat hepatocytes
Stearic acid modifies very low density lipoprotein lipid composition and particle size differently from shorter-chain saturated fatty acids in cultured rat hepatocytes
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DOI：
10.1007/s11745-997-0018-z
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发表时间：
1997-02-01
期刊：
影响因子：
1.9
通讯作者：
Yeh, YY
中科院分区：
文献类型：
--
作者：
Pai, T;Yeh, YY
与肉豆蔻酸酯、棕榈酸酯或油酸酯相比，硬脂酸很难融入三酰甘油中，而三酰甘油是极低密度脂蛋白 (VLDL) 的主要脂质成分。本研究调查了这些脂肪酸对培养的大鼠肝细胞中 VLDL 代谢的影响。所有脂肪酸均刺激 [2-H-3] 甘油掺入 VLDL 脂质中，并刺激肝细胞分泌 [H-3] 标记的 VLDL。然而，在存在非标记硬脂酸盐（12.8 +/- 0.7 pmol/mg 蛋白质/4 小时）的情况下，[H-3] 标记的 VLDL 分泌率分别是肉豆蔻酸盐、棕榈酸盐和油酸盐处理组观察到的 46%、59% 和 22%。 [1-C-14]硬脂酸盐作为底物，与其他标记脂肪酸相比，掺入 VLDL 脂质的效果也较差。在由[1-C-14]硬脂酸酯合成的总VLDL脂质中，三酰甘油占78%，而由棕榈酸酯、肉豆蔻酸酯和油酸酯合成的VLDL脂质占88-97%。在用或不用外源脂肪酸处理的肝细胞中apoB100和apoB48的量是相同的。类似地，从[S-35]甲硫氨酸合成apoB的速率不受外源脂肪酸的影响。各种饱和脂肪酸处理细胞后，VLDL粒径均不同程度增大。在用硬脂酸盐处理的细胞中观察到最大的 VLDL 颗粒，平均直径为 79.3 +/- 11.9 nm，其次是用棕榈酸盐和肉豆蔻酸盐处理的细胞（直径分别为 45.5 +/- 9.8 和 38.6 +/- 6.8 nm）。显然，与用短链饱和脂肪酸处理的肝细胞相比，用硬脂酸盐处理的肝细胞分泌的 VLDL 较少，并产生较大的 VLDL 颗粒。
Stearic acid as compared to myristate, palmitate, or oleate is poorly incorporated into triacylglycerol, a major lipid component of very low density lipoprotein (VLDL). The present study investigated the effects of these fatty acids on VLDL metabolism in cultured rat hepatocytes. All fatty acids stimulated [2-H-3] glycerol incorporation into VLDL lipids and secretion of [H-3]-labeled VLDL by hepatocytes. However, the rate of [H-3]-labeled VLDL secretion in the presence of nonlabeled stearate (12.8 +/- 0.7 pmol/mg protein/4 h) was 46, 59, and 22% of that observed for those treated with myristate, palmitate, and oleate, respectively. [1-C-14]Stearate as a substrate was also less effective than other labeled fatty acids to be incorporated into VLDL lipids. Of total VLDL lipids synthesized from [1-C-14] stearate, triacylglycerol accounted for 78% as compared to 88-97% of that derived from palmitate, myristate, and oleate. The amounts of apoB100 and apoB48 were the same in hepatocytes treated with or without exogenous fatty acids. Similarly, the rate of apoB synthesis from [S-35] methionine was not affected by exogenous fatty acids. The treatment of cells with various saturated fatty acids increased the particle size of VLDL to different extents. The largest particles of VLDL, with a mean diameter of 79.3 +/- 11.9 nm, were seen in the cells treated with stearate, followed by those treated with palmitate and myristate (45.5 +/- 9.8 and 38.6 +/- 6.8 nm, diameter, respectively). Clearly, hepatocytes treated with stearate secrete less VLDL and produce larger VLDL particles than those treated with shorter-chain saturated fatty acids.