Figure 2. Calcium responses in ROSALacZ:MIP1-CreERT islets. Representative traces show changes in Fura 2 fluorescence, which reflects changes in intracellular calcium in isolated mouse islets: (A) ROSA-LacZ:MIP1-CreERT[oil] males; (B) ROSA-LacZ:MIP1-CreERT[Tmx] males. Period of Ca2+ oscillation in islets was 6.7 ± 1.8 min for [Tmx]-injected and 5.9 ± 1.6 min for [oil]-injected; n = 20 islets in each group; differences in Ca2+ oscillations were not statistically significant P = 0.67). (C) - islets from (A and B) stained for β-galactosidase activity (blue color) to show minimal leakiness of Cre activity in control (ARROW) compared with Tmx-treated mice.