- 作者：Radhakrishnan Selvi ; Renganathan Bhuvanasundar ; Aluru Venkata Saijyothi ; Konerirajapuram Natarajan Sulochana ; Narayanasamy Angayarkanni ; drak@snmail.org
- 关键词：Amino acids ; Glucose ; IRTK ; PI3K ; Akt ; GLUT4
- 刊名：Archives of Medical Research
- 出版年：2012
- 期刊代码：24_01884409
- 类别：med
- 出版时间：April, 2012
- 卷：43
- 期：3
- 页码：173-182
- 文件大小：825 K
Background and Aims
Amino acids reportedly increase the glucose uptake under high glucose conditions. However, there are controversies in the role of amino acids in diabetes mellitus. The present study explores the insulin signaling pathway involved in glucose uptake mediated by amino acids in CHO-K1 cells.Methods
CHO-K1 cells were exposed to normal (7 mM) and high glucose (17 and 27 mM) with 100 nM insulin in the presence and absence of amino acid mixtures (AAM) in varying concentration (5 and 20 mM) followed by the assays, insulin receptor tyrosine kinase (IRTK) and phosphatidylinositol 3 kinase (PI3K) by autoradiography, protein kinase B (Akt) and glucose transporter (GLUT4) by Western blot and glycogen synthase (GS) by HPLC.
Results
The addition of 5 and 20 mM AAM significantly increased IRTK and PI3K activity (ANOVA p聽= 0.025, p聽= 0.003, respectively) with increasing glucose concentration. Addition of 5 mM AAM in the presence of normal glucose significantly increased the levels of phosphorylated Akt Ser473 (p聽= 0.02) with no significant change at high glucose. At 20 mM AAM there was a significant decrease in Akt phosphorylation (p聽= 0.035) that was increased by high glucose concentration. GLUT4 protein levels were increased with AAM (5 mM) along with increase in glycogen synthase activity at all glucose concentrations (p <0.05).
Conclusions
Amino acids as a mixture is beneficial in augmenting insulin signaling pathway via IRTK/PI3K/GLUT4 pathway along with activation of GS in CHO-K1 cells, thereby ensuring increased intracellular glucose availability.