高糖膳食对大鼠肝实质及非实质细胞VLDL HDL及载脂蛋白CⅢ受体的影响

Effects of High-Carbohydrate Diet on VLDL-, HDL-, and Apolipoprotein CⅡ-Receptor Activities on Liver Parenchymal and Non-Parenchymal Cells in Rats

对高糖膳食诱发的内源性高甘油三酯血症大鼠肝脏VLDL、HDL及载脂蛋白(apo)CⅢ的受体功能进行了研究。发现肝非实质细胞VLDL受体存在下降调节机理;VLDL及HDL的受体除了受血浆脂蛋白浓度的下降或上升调节外,还可能与apoCⅢ受体活性的增加有关。

We studied the functions ofhepatic VLDL-, HDL--, and apolipoprotein(apo) CⅢ-receptors in the endogenoushypertriglyceridemic (HTG) rats inducedby feeding a high-carbohydrate diet(HCD) (80% of total calories). Compared withthe control rats (60% of total calories inCHO), the fasting plasma triglyceride(TG) levels of the ra's fed on the CHOdiet for 5 days increased by 113.4% (P<0.025. n=6), but HDL-C and total cho-lesterol concentrations decreased by 28.4%and 14.4% (P<0.05, P<0.05). The bind-ing (B_(max)) and uptake of ^(125)I-labeledVLDL by liver non-parenchymal cells(NPC) from HTG rats decreased by 65.0%and 19.1% (P<0.001,P>0.05) respectively.The binding of ^(125)I-labeled apoE-deficient HDL_3 to the NPC also decreasedsignificantly (-54.5%, P<0.05). But theaffinities (Ka) of the two receptors wereprone to increasing. However. the activi-ties of VLDL-and HDL-receptors on liverparenchymal cells didn't significantlychange. Meanwhile, the specific bindingof ^(125)I-labeled apo CⅢ to NPC from HTGrats increased by 104.5% (P<0.025). Theresults of this study suggest that hepaticVLDL-and HDL-receptors could be down-and up-regulated respectively in responseto plasma lipoprotein concentrations inthe high CHO dietary rats, and apo CⅢ-receptor might play an important rolein regulating VLDL- and HDL-receptoractivities.