Figure 2

L-arginine stimulates insulin secretion in Hepa1-6 cells expressing human insulin via the nitric oxide pathway. A. Hepa1-6 cells incubated with the human insulin adenovirus were transferred to 1 mM glucose with or without 20 mM L-arginine in the presence or absence of the NOS inhibitor L-NNA (100 μM) for 1 h. The amount of secreted insulin in the medium was determined and is expressed as fold difference, where insulin secretion on 1 mM glucose was set as 1-fold. Values are expressed as means ± SD for n = 5 in each group. B. Effect of NO donor sodium nitroprusside (SNP) on insulin secretion in Hepa1-6 cells. Insulin secretion in Hepa1-6 cells incubated with the human insulin adenovirus was measured after incubation of cells with 1 mM glucose, with or without 20 mM L-arginine or 100 μM SNP for 1 h (n = 3).