Lagrost L, Barter P J
Graduate School of Health and Medical Sciences, University of Wollongon, Australia.
Biochim Biophys Acta. 1991 Sep 11;1085(2):209-16. doi: 10.1016/0005-2760(91)90096-z.
The effects of saturated, monounsaturated and polyunsaturated non-esterified fatty acids on the rate of transfer of radiolabeled cholesteryl esters from high density lipoproteins (HDL) to low density lipoproteins (LDL), induced by the cholesteryl ester transfer protein (CETP), have been studied. Human high-density lipoproteins-subfraction 3 (HDL3) containing radiolabeled cholesteryl esters were incubated with LDL at 37 degrees C with or without CETP and in the absence or in the presence of non-esterified fatty acids. Less than 6% of the total radioactivity was recovered in the LDL fraction after incubation of HDL3, and LDL for 3 h at 37 degrees C in the absence of CETP, regardless of whether or not non-esterified fatty acids were added. The addition of CETP to the incubation mixture induced a time-dependent redistribution of radiolabeled cholesteryl esters from HDL3 to LDL. Non-esterified fatty acids were found to alter the rate of transfer of cholesteryl esters induced by CETP. While short chain saturated non-esterified fatty acids (caprylic and capric acids) had no effect on the rate of transfer of cholesteryl esters, the medium and long chain ones (lauric, myristic, palmitic and stearic acids) significantly increased the CETP-mediated transfers from HDL3 to LDL. At low concentrations, unsaturated fatty acids also stimulated the CETP-mediated redistribution of radiolabeled cholesteryl esters from HDL3 to LDL. As the concentration of either oleic, linoleic or arachidonic acids increased to higher levels, a significant proportion of fatty acids remained unassociated with lipoprotein particles. Under these circumstances the transfer process was inhibited. These results show that non-esterified fatty acids can modulate the CETP-mediated transfer of cholesteryl esters from HDL to LDL and that this effect is dependent on both the length and the degree of unsaturation of their monomeric carbon chain.
研究了饱和、单不饱和及多不饱和非酯化脂肪酸对胆固醇酯转运蛋白（CETP）诱导的放射性标记胆固醇酯从高密度脂蛋白（HDL）向低密度脂蛋白（LDL）转移速率的影响。将含有放射性标记胆固醇酯的人高密度脂蛋白亚组分3（HDL3）与LDL在37℃下孵育，分别添加或不添加CETP，以及添加或不添加非酯化脂肪酸。在无CETP的情况下，HDL3与LDL于37℃孵育3小时后，LDL组分中回收的总放射性不到6%，无论是否添加非酯化脂肪酸。向孵育混合物中添加CETP会导致放射性标记胆固醇酯从HDL3向LDL发生时间依赖性重新分布。发现非酯化脂肪酸会改变CETP诱导的胆固醇酯转移速率。短链饱和非酯化脂肪酸（辛酸和癸酸）对胆固醇酯转移速率无影响，而中链和长链脂肪酸（月桂酸、肉豆蔻酸、棕榈酸和硬脂酸）显著增加了CETP介导的从HDL3向LDL的转移。在低浓度下，不饱和脂肪酸也会刺激CETP介导的放射性标记胆固醇酯从HDL3向LDL的重新分布。随着油酸、亚油酸或花生四烯酸浓度升高，相当一部分脂肪酸未与脂蛋白颗粒结合。在这种情况下，转移过程受到抑制。这些结果表明，非酯化脂肪酸可调节CETP介导的胆固醇酯从HDL向LDL的转移，且这种作用取决于其单体碳链的长度和不饱和度。
