Effects of insulin and IGF-I on growth hormone- induced STAT5 activation in 3T3-F442A adipocytes.
Effects of insulin and IGF-I on growth hormone- induced STAT5 activation in 3T3-F442A adipocytes.
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胰岛素和 IGF-I 对生长激素诱导的 3T3-F442A 脂肪细胞 STAT5 激活的影响
DOI：
10.1186/1476-511x-12-56
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发表时间：
2013-04-30
影响因子：
4.5
通讯作者：
Wang X
中科院分区：
文献类型：
--
作者：
Zhang Y;Liu Y;Li X;Gao W;Zhang W;Guan Q;Jiang J;Frank SJ;Wang X
生长激素 (GH) 和胰岛素信号通路是已知的脂肪稳态的重要调节因子。成熟脂肪细胞中 GH 和胰岛素信号通路之间的交互作用尚不清楚。在本研究中，检查了胰岛素对分化的 3T3-F442A 脂肪细胞和原代小鼠脂肪细胞中 GH 介导的信号传导的影响。单独使用胰岛素不会诱导 STAT5 酪氨酸磷酸化，但会增强 GH 诱导的 STAT5 激活。当 GH 治疗前 20 分钟添加胰岛素时，这种效果更为明显。体内研究进一步证实了上述结果，表明胰岛素预处理增强了C57/BL6小鼠内脏脂肪组织中GH诱导的STAT5酪氨酸磷酸化。此外，我们的体外结果表明，IGF-I 对 GH 诱导的 STAT5 激活具有与胰岛素类似的增强作用。在体外，胰岛素和 IGF-I 对 GH 诱导的 MAPK 激活具有累加效应。这些结果表明胰岛素和 IGF-I 特异性增强成熟脂肪细胞中 GH 介导的 STAT5 激活。这些发现表明，通常具有拮抗功能的胰岛素和 GH 可能协同作用，调节成熟脂肪细胞的某些特定功能。
Growth hormone (GH) and insulin signaling pathways are known important regulators of adipose homeostasis. The cross-talk between GH and insulin signaling pathways in mature adipocytes is poorly understood. In the present study, the impact of insulin on GH-mediated signaling in differentiated 3T3-F442A adipocytes and primary mice adipocytes was examined. Insulin alone did not induce STAT5 tyrosine phosphorylation, but enhanced GH-induced STAT5 activation. This effect was more pronounced when insulin was added 20 min prior to GH treatment. The above results were further confirmed by in vivo study, showing that insulin pretreatment potentiated GH- induced STAT5 tyrosine phosphorylation in visceral adipose tissues of C57/BL6 mice. In addition, our in vitro results showed that IGF-I had similar potentiating effect as insulin on GH-induced STAT5 activation. In vitro, insulin and IGF-I had an additive effect on GH- induced MAPK activation. These results indicate that both insulin and IGF-I specifically potentiated GH mediated STAT5 activation in mature adipose cells. These findings suggest that insulin and GH, usually with antagonistic functions, might act synergistically to regulate some specific functions in mature adipocytes.