Fig. 4.

Effects of UCP2 over-expression on cellular [Ca²⁺] changes in islets exposed to glucotoxic conditions. At the end of the 7-day culture period at either standard glucose (11 mM) or glucotoxic condition (30 mM), cellular [Ca²⁺] changes were monitored in WT and RIP-UCP2 as ratiometric measurements of Fura-2 fluorescence. Islets were first kept at low 2.8 mM glucose before raising glucose to 22.8 mM (Glucose), as indicated. Finally, 1 µM thapsigargin was added to release Ca²⁺ from the endoplasmic reticulum. Signals were acquired every 10 s. Data were calculated as 340/380 ratio from an average of islets from 3 mice in each condition (A) and then normalized to low glucose levels (B). Values are means ± SE; *p < 0.05 wt 30 versus WT 11 (orange*) and RIP-UCP2 30 versus RIP-UCP2 11 (blue*), #p < 0.05 RIP-UCP2 11 versus WT 11. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)