【摘要】 本文研究了实验性高胆固醇血症大鼠肝及小肠中低密度脂蛋白（ＬＤＬ）受体ｍＲＮＡ和载脂蛋白（ａｐｏ）Ａ－１ｍＲＮＡ的水平变化以及苯甲酸雌二醇（ＥＢ）对二者的影响。发现高脂（ＨＣ）组肝及小肠ＬＤＬ受体ｍＲＮＡ水平分别低于正常组５０％和６０％（Ｐ＜０．０５），小肠ａｐｏＡ－１ｍＲＮＡ水平低于正常组５８％（Ｐ＜０．０５），此时血清总胆固醇（ＴＣ）及ＬＤＬ胆固醇（ＬＤＬ－ｃ）均明显高于正常组（Ｐ＜０．０１），血清ａｐｏＡ－１低于正常组（Ｐ＜０．０５）。ＨＣ＋ＥＢ组血清ＴＣ及ＬＤＬ－ｃ明显低于ＨＣ组，而肝ＬＤＬ受体ｍＲＮＡ水平则显著高于ＨＣ组，为ＨＣ组的３．５倍（Ｐ＜０．００２）。结果提示：（１）高胆固醇负荷时细胞可通过转录水平下行调节ＬＤＬ受体；（２）小肠可能在ａｐｏＡ－１的代谢中起重要作用；（３）ＥＢ可能通过诱导肝ＬＤＬ受体基因表达而降血脂。更多还原

【Abstract】 Low density lipoprotein(LDL)receptor mRNA and apolipoprotein (apo)A-1 mRNA levels of liver and small intestine in experimental hypercholesterolemic ratswere measured,and influences of estradiol benzoaite(EB)on them were studied.It wasobserved that experimental hypercholesterolemic(HC)rats had LDL receptor mRNA levelsin liver and small intestine 50% and 60% respectively lower than the control rats.WhileapoA-1 mRNA levels in small intestine was 58% lower than normal rats,HC rats hadhigher levels of serum total cholesterol(TC)and LDL-cholestrol(LDL-c)and lower levelof serum apoA-1 than normal rats.The rats given EB had lower TC and LDL-c levelin serum than HC rats,and had a much higher hepatic LDL receptor mRNA level,whichwas 3.5 times as high as that of HC rats.These findings suggested:(1) LDL receptor incholesterol-loaded rats was regulated downward at the transcriptional level;(2)small inte-stint may play an important role in apoA-1 metabolism;and(3)it may account for theeffect or lowering serum TC and LDL-c levels that EB induces LDL receptor gene ex-pression in liver.更多还原