Swift L L, Soulé P D, Gray M E, LeQuire V S
J Lipid Res. 1984 Jan;25(1):1-13.
Hypercholesterolemia, induced by a cholesterol-enriched diet, is associated with distinctive modifications in the serum lipoproteins of a variety of species. Present in the serum of these animals are several classes of lipoproteins enriched in cholesteryl esters and apolipoprotein E. To investigate the role of intestinal lipoprotein synthesis in diet-induced hypercholesterolemia, we characterized nascent lipoproteins retrieved from Golgi apparatus-rich fractions of intestinal epithelial cells from chow-fed control and hypercholesterolemic rats. To eliminate chylomicrons from the preparations, rats were fasted overnight prior to the experiments. Golgi very low density lipoproteins (d less than 1.006 g/ml) from control rats were triglyceride-rich lipoproteins that migrated slightly slower than pre-beta migrating serum very low density lipoproteins. These particles contained apoproteins B-240, A-IV, and A-I. Golgi very low density lipoproteins from hypercholesterolemic rats were likewise triglyceride-rich lipoproteins migrating electrophoretically like control Golgi very low density lipoproteins and they contained apoproteins B-240, A-IV, and A-I. However, these latter particles contained less triglyceride and more cholesterol compared to control Golgi very low density lipoproteins. In addition, by radioisotope incorporation studies, Golgi very low density lipoproteins from hypercholesterolemic rats contained relatively more apoprotein A-IV (21.6 vs. 11.0%) and less apoprotein B-240 (17.0 vs. 27.0%) than found in control Golgi very low density lipoproteins. Approximately 60% of the total apoprotein radioactivity was found in apoprotein A-I in both preparations. We conclude that intestinal lipoprotein synthesis is modified by diet-induced hypercholesterolemia. The significance of these modifications with respect to the marked hypercholesterolemia observed in these animals remains to be determined.
由富含胆固醇的饮食诱导的高胆固醇血症与多种物种血清脂蛋白的显著改变有关。这些动物的血清中存在几类富含胆固醇酯和载脂蛋白E的脂蛋白。为了研究肠道脂蛋白合成在饮食诱导的高胆固醇血症中的作用，我们对从正常饮食的对照大鼠和高胆固醇血症大鼠的肠道上皮细胞富含高尔基体的部分中提取的新生脂蛋白进行了表征。为了从制剂中去除乳糜微粒，在实验前大鼠禁食过夜。对照大鼠的高尔基体极低密度脂蛋白（密度小于1.006 g/ml）是富含甘油三酯的脂蛋白，其迁移速度比前β迁移的血清极低密度脂蛋白略慢。这些颗粒含有载脂蛋白B-240、A-IV和A-I。高胆固醇血症大鼠的高尔基体极低密度脂蛋白同样是富含甘油三酯的脂蛋白，其电泳迁移情况与对照高尔基体极低密度脂蛋白相似，并且它们含有载脂蛋白B-240、A-IV和A-I。然而，与对照高尔基体极低密度脂蛋白相比，这些后者颗粒含有较少的甘油三酯和较多的胆固醇。此外，通过放射性同位素掺入研究，高胆固醇血症大鼠的高尔基体极低密度脂蛋白比对照高尔基体极低密度脂蛋白含有相对更多的载脂蛋白A-IV（21.6%对11.0%）和更少的载脂蛋白B-240（17.0%对27.0%）。在两种制剂中，约60%的总载脂蛋白放射性存在于载脂蛋白A-I中。我们得出结论，饮食诱导的高胆固醇血症会改变肠道脂蛋白的合成。这些改变对于在这些动物中观察到的明显高胆固醇血症的意义仍有待确定。
