Fig. 6.

Effects of UCP2 over-expression and of oxidative stress on UCP2 levels and insulin secretion. Isolated WT and RIP-UCP2 islets were subjected to transient oxidative stress (200 µM H₂O₂ for 10 min). Then, islets were either collected immediately (Acute ox-stress, A, C) or after a 3-day recovery period (Post ox-stress 3 days, B, C). (A, B) UCP2 protein levels, normalized to ß-actin, were assessed by immunoblotting. Bar-graphs show averages of 3 individual experiments. (C) Insulin secretion over a 1 h incubation at either 2.8 mM glucose (Low) or stimulatory 22.8 mM glucose (Stim) was determined both directly after the 10 min transient ox-stress (Acute stress) and 3 days after H₂O₂ exposure (3 days after stress), and compared with islets not exposed to H₂O₂ (No stress). *p < 0.05 versus corresponding Low of the same genotype in the same condition; ##p < 0.01 versus corresponding condition in No stress; &, p < 0.05 versus corresponding WT of the same stress.