Leptin对猪原代脂肪细胞脂解及其关键脂酶mRNA表达的影响

Leptin是由脂肪组织分泌的内源因子,在调节机体能量平衡过程中起重要作用.Leptin促进脂解的研究由来已久,但其作用机理尚不完善.本研究旨在通过系统检测关键脂酶mRNA的表达变化来探讨Leptin促进脂解的分子机理.运用形态学观察,油红O染色和RT-PCR鉴定培养的猪原代脂肪细胞;甘油测定试剂盒和游离脂肪酸(FFA)测定试剂盒分别检测甘油和FFA的释放;半定量RT-PCR检测关键脂酶mRNA的表达.结果显示:100 nmol/L的Leptin可显著上调ATGL、TGH-2、HSL、MGL和LPL mRNA的表达(P<0.01),但同时下调Perilipin mRNA的表达(P<0.01);Leptin呈浓度依赖性促进甘油的释放(P<0.01),但对FFA的释放影响不显著(P>0.05).以上结果提示,Leptin可能主要通过上调ATGL、MGL、LPL和下调Perilipin的表达促进猪原代脂肪细胞的脂解;同时推测,FFA释放的相对稳定可能是由Leptin通过上调UCPs的表达而增加FFA的消耗引起的.

Effects of Leptin on Porcine Primary Adiocytes Lipolysis and mRNA Expression of Key Lipolytic Enzymes

Leptin, a cytokine predominantly secreted from fat tissue, plays an important role in regulating organism energy balance. Leptin can stimulate lipolysis, but the mechanism is unclear. In order to study the molecular mechanism of leptin stimulating lipolysis, we systemically studied the mRNA expression of key lipolytic enzymes. Morphological observation, Oil Red O staining and RT- PCR were used to identify pig primary adipocytes; commercial kits were used to measure the glycerol and FFA release; Semiquantitative RT-PCR was used to detect the mRNA expression of key lipolytic enzymes. The results showed that 100 nmol/L leptin up-regulated the mRNA expression of ATGL, TGH-2, HSL, MGL and LPL (P<0.01), but down-regulated the Perilipin mRNA expression (P<0.01). At the same time, leptin promoted the glycerol release in a dose dependent manner (P<0.01), but had no effect on the FFA release (P>0.05). These indicate that leptin may mainly stimulate lipolysis in pig primary adipocytes by up-regulating the expression of ATGL, MGL, LPL and down-regulating the expression of Perilipin. The unchanged FFA release may be resulted from Leptin promoting UCPs mRNA expression and increasing FFA expenditure.