title: Effect of metformin on insulin-resistant endothelial cell function.
abstract: The aim of the present study was to investigate the effect of metformin on the function of insulin-resistant (IR) endothelial cells. A model of IR endothelial cells was established by incubating cells with 30 mM glucose, 1 μM dexamethasone and various concentrations of insulin. The nitric oxide (NO) content of the endothelial cells was determined by measuring the rate of nitroreductase production; the endothelin (ET) concentration was examined by enzyme-linked immunosorbent assay; and the expression levels of endothelial nitric oxide synthase (eNOS) were detected using western blotting. The optimal conditions for inducing insulin resistance in endothelial cells were a combination treatment of 10-4mmol/l insulin, 30 mM glucose and 1 μM dexamethasone for 48 h. Notably, metformin administration significantly increased the NO content and reduced the ET-1 concentration in the IR cells compared with the non-treated control cells (P<0.05); furthermore, metformin significantly increased the intracellular eNOS protein expression in IR endothelial cells compared with the non-treated control cells (P<0.05), with an optimal metformin concentration of 10-3mmol/l. Thus, the present study identified that metformin improves the function of IR endothelial cells, possibly through promoting eNOS protein expression and increasing the NO content.
authors: Cadre Ward, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China.
authors: Haiyan
authors: H
authors: Chen
authors: Cadre Ward, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China.
authors: Jie
authors: J
authors: Li
authors: Cadre Ward, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China.
authors: Ou
authors: O
authors: Yang
authors: Cadre Ward, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China.
authors: Jian
authors: J
authors: Kong
authors: Department of Cardiology, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China.
authors: Guangzhu
authors: G
authors: Lin
keywords: endothelial cells; endothelial nitric oxide synthase; insulin resistance; metformin; nitric oxide