Li M, Li C, Parkhouse W S
Metabolic Biochemistry Laboratory, School of Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada.
Mol Cell Biochem. 2002 Jul;236(1-2):115-22. doi: 10.1023/a:1016164601887.
Alterations in the degree of the phosphorylation of ERKI/2, Akt-1 and p70 S6K in mouse skeletal and cardiac muscle was examined in vivo following an intraperitoneal injection of des IGF-I. Plasma levels of insulin, IGF-I and glucose were measured. The administration of des IGF-I had no effect on plasma levels of insulin, or IGF-I, but plasma glucose levels were decreased about 50% (p < 0.01). In both skeletal and cardiac muscle, des IGF-I increased the phosphorylation of Akt-1 at Ser 473 (p < 0.01) with no change in the phosphorylation of p44 and p42 MAP kinases at Thr202/Tyr204. The phosphorylation of p70 S6K at Thr421/Ser424 was increased in skeletal muscle (p < 0.01), but not in cardiac muscle. The phosphorylation of the nuclear transcription factor CREB phosphorylation at Ser 133 was not significantly changed in either skeletal or cardiac muscle. Des IGF-I increased the phosphorylation of the transcription factor FKHR in cardiac muscle only (p < 0.05). These data demonstrate that the administration of des IGF-I had differential effects on the activation of the MAP kinase and PI 3-kinase pathways in mouse skeletal and cardiac muscle.
在腹腔注射去胰岛素样生长因子-I（des IGF-I）后，对小鼠骨骼肌和心肌中细胞外信号调节激酶1/2（ERKI/2）、蛋白激酶B-1（Akt-1）和核糖体蛋白S6激酶（p70 S6K）的磷酸化程度变化进行了体内研究。检测了胰岛素、胰岛素样生长因子-I和葡萄糖的血浆水平。给予des IGF-I对胰岛素或胰岛素样生长因子-I的血浆水平没有影响，但血浆葡萄糖水平降低了约50%（p < 0.01）。在骨骼肌和心肌中，des IGF-I均增加了Akt-1在丝氨酸473位点的磷酸化（p < 0.01），而苏氨酸202/酪氨酸204位点的p44和p42丝裂原活化蛋白激酶（MAP激酶）的磷酸化没有变化。p70 S6K在苏氨酸421/丝氨酸424位点的磷酸化在骨骼肌中增加（p < 0.01），但在心肌中没有增加。核转录因子cAMP反应元件结合蛋白（CREB）在丝氨酸133位点的磷酸化在骨骼肌和心肌中均无显著变化。des IGF-I仅增加了心肌中转录因子叉头转录因子O1（FKHR）的磷酸化（p < 0.05）。这些数据表明，给予des IGF-I对小鼠骨骼肌和心肌中MAP激酶和磷脂酰肌醇3激酶（PI 3-激酶）信号通路的激活具有不同的影响。
