Antioxidant effect of angiotensin (1-7) in the protection of pancreatic β cell function

It is well known that the local renin-angiotensin system (RAS) is activated in the diabetic state, which results in an increase in the level of oxidative stress injury to pancreatic β cells. The angiotensin-converting enzyme 2 (ACE2)/angiotensin (1-7) [Ang (1-7)]/Mas axis is a negative regulator of the classical renin-angiotensin system. In order to investigate the antioxidant effect of Ang (1-7) on pancreatic β cells, INS-1 cells were cultured and oxidative stress was induced by treatment with H(2)O(2). Glucose-stimulated insulin secretion (GSIS), the generation of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and glucose-stimulated calcium (GSCa) responses in β cells were determined following treatment with Ang (1-7). It was observed that H(2)O(2) significantly impaired the insulin secreting function, increased the production of ROS, and also decreased the levels of GSCa and MMP. Pre-treatment with Ang (1-7) alleviated these effects and treatment with A779 [antagonist of Ang (1-7)] prevented the effects of Ang (1-7). Based on these findings, it was concluded that Ang (1-7) can protect pancreatic β cells from oxidative injury and such protection can be blocked by its antagonist A779.