下丘脑腹内侧核损伤性肥胖大鼠动力相脂肪代谢研究

THE LIPOGENIC AND LIPOLYTIC METABOLISM AT DYNAMIC PHASE OF OBESITY IN VENTROMEDIAL HYPOTHALAMUS-LESIONED OBESE RATS

目的 : 探讨下丘脑腹内侧核损伤性肥胖大鼠在肥胖形成动力相中脂肪合成与分解代谢的变化。方法 : 雌性 SD大鼠分为下丘脑腹内侧核损伤肥胖组 (VMH)和下丘脑腹内侧核非损伤对照组 (sham) ,于下丘脑腹内侧核损伤和伪性损伤 1 w后 ,留取肝脏、皮下脂肪、子宫外周和肠系膜脂肪组织以及腓肠肌分别测定脂肪合成和分解酶活性。结果 : VMH组大鼠肝脏微粒体甘油三酯转运蛋白、肝脏以及子宫外周和肠系膜脂肪组织的磷脂酰磷酸水解酶、苹果酸酶、葡萄糖 - 6 -磷酸脱氢酶活性均高于对照组。与对照组相比 ,VMH组子宫外周和肠系膜脂肪组织激素敏感脂酶(HSL )活性没有变化 ,皮下脂肪组织的 HSL活性升高 ,相反腓肠肌的 HSL活性下降。在 VMH组 ,皮下脂肪组织、子宫外周脂肪组织、肠系膜脂肪组织以及腓肠肌中的脂蛋白脂酶活性均升高。结论 : 在动力相 ,VMH肥胖大鼠肝脏合成和转运甘油三酯能力 ,以及脂肪组织如子宫外周和肠系膜脂肪组织的脂质合成和储存增强 ;另一方面 ,肌肉组织和皮下脂肪组织的脂肪分解也增强。

Objective: To investigte the lipogenic and lipolytic metabolism at dynamic phase of obesity in ventromedial hypothalamus-lesioned obese rats. Methods: Female SD rats were divided into two groups, one group received bilateral electrolytic lesions of ventromedial hypothalamus(VMH),and the other one was used as sham control. Samples of blood, livers and subcutaneous, parametric and mesenteric adipose tissues were collected one week after VMH lesions and sham operations. Results: Activities of microsomal triglyceride transfer protein(MTP) in hepatocytes, and phosphatidate phosphohydrolase (PAP), malic enzyme(ME), glucose-6-phosphate dehydrogenase(G6PDH)in liver, parametric and mesenteric adipose tissue in VMH-lesioned rats were increased as compared to their sham counterparts. Activity of hormone sensitive enzyme(HSL) in parametric and mesenteric adipose tissue in VMH-lesioned rats was not changed when compared to sham group. Activity of HSL in subcutaneons adipose tissue was increased, while activity of HSL in gastrocnemius was decreased. Activity of lipoprotein lipase(LPL) in parametric and mesenteric adipose tissue and gastrocnemius were enhanced significantly compared to sham group. Conclusion: In dynamic phase of obesity of VMH-lesioned rats, hepatic production and transportation of triglyceride in these rats were increased significantly ,and lipogenic metabolism and storage of triglyceride in adipose tissues such as parametric and mesenteric adipose tissues were also enhanced.Meanwhile, lipolytic metabolism in subcutaneous adipose tissue and gastrocnemius was also increased.