胰岛素、地塞米松、胰岛素样生长因子-1(IGF-1)对3T3-L1脂肪细胞脂肪水孔蛋白表达的调节作用

目的通过细胞培养研究胰岛素样生长因子-1(IGF鄄1)、地塞米松对成熟脂肪细胞水孔蛋白(Aquaporinadipose,AQPap)基因表达的影响,并与胰岛素的作用相比较,以此了解AQPap基因表达的影响因素,探讨其在肥胖及糖尿病发病中所起作用。方法用不同浓度(10-6、10-7、10-8、10-9mol/L)的胰岛素、IGF鄄1(10-7、10-8、10-9、10-10mol/L)及地塞米松刺激液(10-6、10-7、10-8mol/L)刺激诱导分化第9天的3T3鄄L1细胞6h;提取细胞RNA,运用半定量RT鄄PCR技术,检测AQPapmRNA表达量的变化。结果与对照组相比,10-9mol/L胰岛素刺激细胞6h可使AQPap基因表达下降16%,10-6mol/L胰岛素使之下降超过50%。IGF鄄1也降低AQPap的基因表达,但相同浓度(10-7mol/L)刺激下,IGF鄄1的作用要弱于胰岛素(P<0.05)。地塞米松对AQPapmRNA的表达量无明显影响,不过,同时给予10-6mol/L的地塞米松和胰岛素与单用10-6mol/L胰岛素相比,AQPapmRNA的表达量有所上升(P<0.05)。结论胰岛素对3T3鄄L1脂肪细胞AQPap的表达起抑制作用,并呈剂量及时间依赖性。IGF鄄1也有抑制作用,但较胰岛素弱。地塞米松能够拮抗胰岛素对3T3鄄L1脂肪细胞AQPap基因表达的下调作用。

Effect of Insulin,Dexamethasone,IGF-1 on AQPap mRNA Expression in 3T3-L1 Adipocytes

Objective: To investigated the effect of hormone such as insulin, IGF-1 and dexamethasone on expression of AQPap in 3T3-L1 adipocytes, in order to know the role of AQPap in obesity and diabetes mellitus. Methods: 3T3-L1 cells on day 9 after differentiation were incubated with 10-6, 10-7, 10-8 and 10-9 mol/L insulin for 6 h, or incubated in DMEM with 10-8 mol/L insulin for 0, 3, 6 h for the experiment on time course, and total cellular RNA were extracted and used for RT-PCR. Such cells were also stimulated by IGF-1(10-7, 10-8, 10-9, 10-10 mol/L), dexamethasone(10-6, 10-7, 10-8 mol/L) or insulin(10-6 mol/L) + dexamethasone(10-6 mol/L) respectively, and total RNA was isolated for RT-PCR. Results: Treatment with 10-9 mol/L insulin suppressed AQPap mRNA expression in differentiated 3T3-L1 adipocytes(P < 0.05), and the results showed that the suppression of insulin on the expression of AQPap mRNA was dose-dependent and time-dependent in 3T3-L1 cells. IGF-1 could also decrease AQPap mRNA expression in differentiated 3T3-L1 adipocytes in 10-7 mol/L, but the suppression was weak compared to insulin with the same concentration. Desamethasone had no effect on the expression of AQPap mRNA in 3T3-L1 cells, but it could decrease the inhibition of insulin on the AQPap gene expression. Conclusion: Insulin is a negative regulator of AQPap expression. The inhibition of IGF-1 on AQPap expression is less than that of insulin at the same stimulation concentration. Dexamethasone can antagonize the negative regulation of insulin on AQPap expression.