雌、雄激素对雄性大鼠血脂代谢及肝血脂代谢相关酶的影响

The effects of androgen and estradiol on blood lipid metabolism and the correlated enzyme of hepatic blood lipid metabolism in male rats

目的探讨雌、雄性激素对雄性大鼠血脂代谢和肝血脂代谢相关酶的影响。方法24只雄性SD大鼠(320±20)g随机分为去势对照组(ORX组)、去势二氢睾酮(DHT)(DHT组)、去势雌二醇组(E2)(E2组)和正常对照组(对照组),每组6只。ORX组、DHT组、E2组行去势手术,对照组进行假手术。DHT组皮下注射DHT溶液(0.6mg.kg-1.d-1,医用玉米油为溶剂),E2组皮下注射E2(0.2mg.kg-1.d-1,医用玉米油为溶剂);对照组、ORX组注射医用玉米油(安慰剂)。各组动物饲喂高胆固醇高脂肪饮食,于14w后处死全部实验动物,酶法测定各类脂蛋白胆固醇及血脂等指标;酶免法(ELISA)测定血浆DHT浓度,放免法检测血浆睾酮(T)、E2水平。称量各组动物的体重和肝脏湿重,取肝脏组织处理,测定血脂相关代谢酶。结果血浆T浓度DHT组、ORX组和E2组显著低于对照组(P<0.05);DHT水平DHT组和对照组两组间无统计学差异(P>0.05)。血浆E2水平,E2组显著高于DHT组、ORX组、对照组(P<0.05),DHT组与ORX组组间无统计学差异(P>0.05)。E2组血浆TC明显高于ORX组、DHT组和对照组(P<0.05);ORX组高于DHT组、对照组(P<0.05),但DHT组与对照组间无统计学差异(P>0.05);E2、DHT组血浆TG明显高于对照组(P<0.05);ORX组与对照组无统计学差异(P>0.05);ORX组、E2组血浆HDL-C明显高于DHT组、对照组(P<0.05);DHT组与对照组无统计学差异(P>0.05);E2组血浆HDL-C高于DHT组、ORX组与对照组,但DHT组、ORX组与对照组各组间均无统计学差异(P>0.05)。肝脏HL、LPL、CY7PA1mRNA表达DHT组高于E2组、ORX组与对照组,E2组低于ORX组与对照组(P<0.05)。结论雌激素降低雄性大鼠肝脏HL、LPL、CY7PA1活性,雄激素激活HL、LPL、CY7PA1的表达;雄、雌激素都影响血脂代谢,DHT可导致TC降低,同时伴有TG升高;而E2使TC、LDL升高。

Objective To evaluate the effects of androgen and estradiol on lipid metabolism and correlated enzyme of hepatic lipid metabolism in male rats. Methods 24 male SD rats were randomly divided into orchiectomized （ORX） control group （ ORX group, injected with medical maize oil） , ORX dihydrotestosterone group （ DHT group, injected with medical maize oil dissolved DHT O. 6 mg ·kg^-1·d^-1 ）, ORX estradiol group （ E2 group, injected with medical maize oil dissolved E20. 2 mg·kg^-1·d^-1 ） and sham operation group （ control group, injected with medical maize oil）, 6 rats in each group. All animals fed with high-cholesterol and high-fat diet for 14 weeks were killed to measure plasma lipid （lipoprotein, cholesterol） with enzymic method, plasma DHT by ELSIA and testosterone and E2 by radioimmunoassay （RIA）. The bedyweight and fresh liver weight of all animals were measured. The liver tissues were treated to detect blood lipid metabolism correlated enzyme. Results The level of plasma testosterone was lower in ORX, DHT and E2 group than that in control group （ P 〈0. 05 ）. The level of plasma DHT was not statistically significant between DHT and control group （P 〉0. 05 ）. The level of plasma E2 in E2 group was higher than that in DHT, ORX and control group （ P 〈 0. 05 ）, but there was no significance between DHT and ORX group （ P 〉 0. 05 ）. Plasma total cholesterol （TC） level in E2 group was significantly higher than that in ORX, DHT and control group （ P 〈 0. 05 ）, while that in ORX group was higher than that in DHT and control group （ P 〈 0. 05 ）, but there was no significance between DHT and control group （P 〉0. 05）. Plasma triglyeride （TG） level in E2 and DHT group was higher than that in control group （P 〈0. 05）, but there was no significance between ORX and control group （P 〉0. 05）. Plasma high-density lipoprotein cholesterol （HDL-C） level in ORX and E2 group was higher than that in DHT and control group （ P 〈 0. 05 ）, but there was no significance between DHT and control group （ P 〉 0. 05 ）. Plasma low-density lipoprotein cholesterol （LDL-C） level in E2 group was higher than that in DHT, ORX and control group （P 〈 0. 05 ）, but that in DHT and ORX had no significant difference than that in control group （ P 〉 O. 05 ）. The mRNA level of cholesterol 7α-hydroxylase （CY7PA1）, hepatic lipase （HL） and lipoprotein lipase （LPL） in DHT group were higher than those in E2, ORX and control group, while those in E2 group were lower than those in ORX and control group （ P 〈 0. 05 ）. Conclusions DHT could decrease plasma TC, while increase TG. DHT could activate the expressions of HL, LPL and CY7PA1. E2 could restrain the activity of HL, LPL and CY7PA1. E2 and DHT could influence blood lipid metabolism, but E2 could enhance TC and LDL levels.