| 摘要: | This study is the first to examine the effects of pre-germinated brown rice (PGBR) extract in TNF- impaired insulin stimulated glucose uptake and insulin signaling. HepG2 cells were cultured in DMEM medium and added with 20M insulin or with 20M insulin and 30ng/ml TNF-. The glucose levels of the medium were decreased by insulin, demonstrating insulin promoted glucose uptake into cell. However, TNF- inhibited glucose uptake into cells treated with insulin. Moreover, insulin increased the protein expressions of AMP-activated protein kinase (AMPK), insulin receptor substrate-1 (IRS-1), phosphatidylinositol-3-kinase-(PI3K-), serine/threonine kinase PI3K-linked protein kinase B (Akt/PKB), glucose transporter-2 (GLUT-2), glucokinase (GCK), peroxisome proliferator activated receptor- (PPAR-) and PPAR-. TNF- activated MAPKs (p65, JNK1/2 and ERK1/2) which worsened the expressions of AMPK, IRS-1, PI3K-, Akt/PKB, GLUT-2, GCK, glucogen synthase kinase-3 (GSK-3), PPAR-and PPAR-. Once this relationship was established, we added PGBR extract (50, 100, 300 g/ml) to cell with 20M insulin and 30ng/ml TNF-. We found glucose levels of medium were lowered and that the protein expressions of AMPK, IRS-1, PI3K-, Akt/PKB, GLUT-2, GCK, GSK-3, PPAR-, PPAR- and p65, JNK1/2 were also improved. In conclusion, this study found that TNF- inhibited insulin stimulated glucose uptake and aggravated related proteins expressions, suggesting that it might cause insulin resistance. PGBR extract was found to improve this TNF-induced insulin resistance, suggesting that it might be used in the future to help control insulin resistance. |
