Background: To investigate the effects of a single dose of metformin (MF) on endothelium-dependent vasodilatation and serum antioxidant and free fatty acid levels in patients with primary hypertension (PH) after an acute glucose load.
Materials and methods: Patients with untreated PH were randomized to a no-metformin group (PH, n = 34) and a metformin group (PH+ MF, n = 28) who received a single dose of 500 mg metformin before testing. Healthy volunteers (n = 31) served as a control group. Brachial artery endothelium-dependent flow-mediated vasodilatation (FMD) was determined at 0, 1, 2 and 3 h after glucose load. Levels of serum superoxide dismutase (SOD), total antioxidant capacity (T-AOC), anti-superoxide anion free radical (AntiO2) and free fatty acids (FFA) were measured.
Results: The FMD in the PH group decreased significantly 1 h after glucose load (PH: 10.9 ± 2.9% vs 13.67 ± 3.42% before glucose load). Metformin inhibited the effects of glucose load on FMD. At 1 h after acute glucose load, the concentrations of SOD, T-AOC and AntiO2 in the PH group decreased significantly compared with their fasting levels, and metformin inhibited the acute glucose load-induced decline in SOD and T-AOC levels.
Conclusions: Metformin can prevent transient endothelial dysfunction caused by acute glucose load in patients with PH.