Insulin regulates lipid and glucose metabolism similarly in two lines of rainbow trout divergently selected for muscle fat content
Insulin regulates lipid and glucose metabolism similarly in two lines of rainbow trout divergently selected for muscle fat content
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DOI：
10.1016/j.ygcen.2014.04.027
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发表时间：
2014-08-01
影响因子：
2.7
通讯作者：
Medale, Francoise
中科院分区：
文献类型：
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作者：
Jin, Junyan;Panserat, Stephane;Medale, Francoise
通过针对低（瘦“L”系）或高（胖“F”系）肌肉脂肪含量的发散选择开发了两个实验性虹鳟品系。先前的营养研究表明，这些品系在脂质和葡萄糖代谢的调节方面有所不同。由于胰岛素通过调节脂质和葡萄糖代谢发挥合成代谢激素的作用，因此我们提出假设F系可能比L系对胰岛素具有更强的敏感性。为了检验这一假设，将牛胰岛素注射到禁食48小时的两条虹鳟鱼体内。正如预期的那样，胰岛素诱导了低血糖，并激活了两条细胞系的肝脏和肌肉中的 Akt-TOR 信号传导。我们证明，这与肌肉和肝脏中胰岛素依赖性葡萄糖转运蛋白 (GLUT4) 和脂肪酸合成代谢转录因子 (LXR 和 SREBP1c) 的表达增加，以及两个系白肌肉中脂肪酸氧化酶 (CPT1a、CPT1b 和 HOAD) mRNA 水平的降低有关。关于基因型效应，F 系中 TOR 信号对胰岛素的反应更强，这反映在 F 系肝脏中 S6 蛋白的磷酸化程度较高和脂肪生成酶 (FAS) mRNA 水平升高。这一观察结果与 F 系中较高的游离脂肪酸和甘油三酯血浆浓度一致。此外，F 系中肝糖异生酶（G6Pase2、FBPase 和 PEPCK）和肌肉脂肪酸氧化酶（CPT1a、CPT1b、HOAD 和 ACO）的 mRNA 水平较高。然而，检测到的胰岛素基因型相互作用非常少，这表明胰岛素在两个品系中诱导了相似的脂质和葡萄糖代谢变化。 (C) 2014 Elsevier Inc. 保留所有权利。
Two experimental rainbow trout lines were developed through divergent selection for low (Lean 'L' line) or high (Fat 'F' line) muscle fat content. Previous nutritional studies suggested that these lines differed in their regulation of lipid and glucose metabolism. Since insulin acts as an anabolic hormone by regulating lipid and glucose metabolism, we put forward the hypothesis that F line might have a stronger sensitivity to insulin than L line. In order to test this hypothesis, bovine insulin was injected into rainbow trout of the two lines fasted for 48 h. As expected, insulin induced hypoglycemia and activated Akt-TOR signaling both in the liver and muscle of the two lines. We demonstrate that this was coupled with increased expression of insulin dependent glucose transporter (GLUT4) and transcription factors of fatty acid anabolism (LXR and SREBP1c) in the muscle and liver, respectively, and lower mRNA levels of fatty acid oxidation enzymes (CPT1a, CPT1b and HOAD) in the white muscle of both lines. Regarding the genotype effect, TOR signaling response to insulin was stronger in F line as reflected by the higher phosphorylation of S6 protein and elevated mRNA levels of lipogenic enzyme (FAS) in the liver of F line. This observation was concordant with the higher plasma concentrations of free fatty acids and triglycerides in F line. Moreover, mRNA levels of hepatic gluconeogenic enzymes (G6Pase2, FBPase and PEPCK) and muscle fatty acid oxidation enzymes (CPT1a, CPT1b, HOAD and ACO) were higher in the F line. However, very few insulin-genotype interactions were detected, indicating that insulin induced similar changes in lipid and glucose metabolism in both lines. (C) 2014 Elsevier Inc. All rights reserved.