White D A, Bennett A J, Billett M A, Salter A M
Department of Biochemistry, University of Nottingham Medical School, UK.
Prostaglandins Leukot Essent Fatty Acids. 1997 Oct;57(4-5):455-62. doi: 10.1016/s0952-3278(97)90428-2.
Hamsters were fed diets containing fat (5-20%, w/w) consisting of triolein (TO) alone or 50% triolein plus 50% trimyristin (TM), tripalmitin (TP) or tristearin (TS) for 28 days. Each fat had unique effects on lipoprotein concentrations which were related to changes in the expression of hepatic genes. Tripalmitin was the most hypercholesterolaemic of the saturated fats, causing dose-dependent increases in LDL and HDL cholesterol which correlated with decreases in the expression of HMGCoA reductase and LDL receptor genes. Tripalmitin also increased the expression of the apoB gene. It seems likely that fatty acids may regulate genes which are involved both in the synthesis and clearance of plasma lipoproteins. Inclusion of increasing amounts of cholesterol in diets containing 20% fat (50% TO plus 50% TP or TS) caused down-regulation of HMGCoAR and LDLR genes and up-regulation of the microsomal triglyceride transfer protein (MTP) gene for both fats. This was accompanied by increased LDL-cholesterol in the TP but not the TS group. In all experiments the concentration of VLDL-cholesterol correlated with the hepatic cholesterylester and MTP mRNA concentrations.
给仓鼠喂食含脂肪（5 - 20%，w/w）的日粮，脂肪由单独的三油酸甘油酯（TO）或50%三油酸甘油酯加50%肉豆蔻酸甘油酯（TM）、棕榈酸甘油酯（TP）或硬脂酸甘油酯（TS）组成，持续28天。每种脂肪对脂蛋白浓度都有独特影响，这与肝脏基因表达的变化有关。棕榈酸甘油酯是饱和脂肪中导致高胆固醇血症最明显的，使低密度脂蛋白（LDL）和高密度脂蛋白（HDL）胆固醇呈剂量依赖性增加，这与3-羟基-3-甲基戊二酰辅酶A（HMGCoA）还原酶和LDL受体基因表达的降低相关。棕榈酸甘油酯还增加了载脂蛋白B（apoB）基因的表达。脂肪酸似乎可能调节参与血浆脂蛋白合成和清除的基因。在含20%脂肪（50% TO加50% TP或TS）的日粮中增加胆固醇含量，导致两种脂肪的HMGCoA还原酶（HMGCoAR）和LDL受体（LDLR）基因下调，微粒体甘油三酯转移蛋白（MTP）基因上调。这伴随着TP组而非TS组LDL胆固醇增加。在所有实验中，极低密度脂蛋白（VLDL）胆固醇浓度与肝脏胆固醇酯和MTP信使核糖核酸（mRNA）浓度相关。
