Sulfonylurea as well as elevated glucose levels stimulate reactive oxygen species production in the pancreatic β-cell line, MIN6 : a role of NAD(P)H oxidase in β-cells

Abstract Increased oxidative stress may play a key role in the progressive deterioration of pancreatic β-cells and the development of diabetes. However, the underlying mechanism is not well understood. Exposure of pancreatic β-cell line, MIN6 cells, to elevated glucose level for 2 h induced an increase in reactive oxygen species (ROS) production, as evaluated by the staining of 2′,7′-dichlorofluorescein diacetate. This effect was completely blocked by NAD(P)H oxidase inhibitor (diphenylene iodonium) and protein kinase C (PKC) inhibitor (calphostin C), but not affected by other flavoprotein inhibitors (rotenone, oxypurinol, or l - N -monomethyl arginine). Glibenclamide also stimulated ROS production in a dose-dependent manner. This effect was again blocked by diphenylene iodonium and calphostin C. In conclusion, insulin secretagogues, both glibenclamide and elevated glucose level, stimulated ROS production in β-cells through a PKC-dependent activation of NAD(P)H oxidase. This mechanism may be a novel therapeutic target for preventing the progression of β-cell deterioration.