Fisher R M, Coppack S W, Humphreys S M, Gibbons G F, Frayn K N
Oxford Lipid Metabolism Group, Sheikh Rashid Laboratory, Radcliffe Infirmary, UK.
Clin Chim Acta. 1995 Apr 30;236(1):7-17. doi: 10.1016/0009-8981(95)06032-3.
In order to test the hypothesis that lipoprotein lipase (LPL) acts preferentially on larger lipoprotein particles, we determined the susceptibility of triacylglycerol-rich lipoprotein (TRL) subfractions to hydrolysis by LPL in vitro. Chylomicrons (Sf > 400), very low density lipoproteins (VLDL)1 (Sf 60-400) and VLDL2 (Sf 20-60) were isolated from six subjects with a range of plasma-triacylglycerol (TAG) concentrations following an overnight fast and for up to 6 h after the consumption of a mixed meal (41% fat). The percent of TRL-TAG hydrolysed by LPL in subfractions isolated following overnight fast was VLDL1 > VLDL2 (46.8 +/- 10.2 vs. 25.9 +/- 7.4%, P = 0.006) and 3 h after the meal it was chylomicrons > VLDL1 > VLDL2 (81.0 +/- 12.6 vs. 52.8 +/- 10.2 vs. 27.7 +/- 6.2%, chylomicrons vs. VLDL1 and VLDL1 vs. VLDL2, both P < or = 0.005). The percent of VLDL1-TAG hydrolysed increased both within and between subjects as VLDL1-TAG concentrations increased. This relationship could be explained by the positive correlation observed between VLDL1-TAG and VLDL1-TAG:apolipoprotein B. In conclusion, increasing the size and TAG content of a lipoprotein particle increases its susceptibility to hydrolysis by LPL.
为了验证脂蛋白脂肪酶（LPL）优先作用于较大脂蛋白颗粒的假说，我们在体外测定了富含三酰甘油的脂蛋白（TRL）亚组分对LPL水解的敏感性。从6名受试者中分离出乳糜微粒（Sf>400）、极低密度脂蛋白1（VLDL1，Sf 60 - 400）和极低密度脂蛋白2（VLDL2，Sf 20 - 60），这些受试者在禁食过夜后以及进食混合餐（41%脂肪）后长达6小时内，血浆三酰甘油（TAG）浓度各不相同。禁食过夜后分离的亚组分中，LPL水解的TRL - TAG百分比为VLDL1>VLDL2（46.8±10.2对25.9±7.4%，P = 0.006），进食后3小时则是乳糜微粒>VLDL1>VLDL2（81.0±12.6对52.8±10.2对27.7±6.2%，乳糜微粒对VLDL1以及VLDL1对VLDL2，P均≤0.005）。随着VLDL1 - TAG浓度增加，VLDL1 - TAG水解的百分比在受试者个体内和个体间均升高。这种关系可以通过VLDL1 - TAG与VLDL1 - TAG:载脂蛋白B之间的正相关来解释。总之，脂蛋白颗粒大小和TAG含量的增加会提高其对LPL水解的敏感性。
