The effect of Ginkgo biloba Extract (GB) on Glucose Uptake in L6 Rat Skeletal Muscle Cells

L6 근육세포에서 은행잎 추출물의 당 흡수효과

Objectives: Evidences suggests that Ginkgo biloba, a widely used traditional medicine, shows a hypoglycemic effect. Thus, we investigatd the effect of G. biloba extract (GB) on glucose uptake in L6 rat skeletal muscle cells. Method : Effect of GB on glucose uptake and phosphatidylinositol (PI) 3-kinase activity were assessed using Glucose uptake assay and PI 3-kinase assay, respectively. Also, AMP-activated protein kinase (AMPK), p38 mitogen activated protein kinase (p38 MAPK) expression were identified by Western blot. Results : Glucose uptake assay revealed that GB increased glucose uptake about 2.5-fold compared to thecontrol. GB stimulated the activity of PI 3-kinase which is a major switch element on the glucose uptake pathway. About a 6.5-fold increase in activity of PI 3-kinase was observed with GB. We then assessed the activity of AMPK, another regulatory molecule on the glucose uptake pathway. The result was that GB increased the phosphorylation level of both AMPK ${\alpha}$l and ${\alpha}$2. The activity of p38 MAPK, a downstream mediator of AMPK, was also increased by CB. Conclusion : These results suggest that GB may stimulate glucose uptake through both PI 3-kinase and AMPK mediated pathways in L6 skeletal muscle cells thereby contributing to glucose homeostasis.