Fig 4. ROS content and the effects of oxidative stress on InR1G cells.

(A) ROS content determination. Cells were exposed to regular (11.1 mM, white) or high (25 mM, black) glucose levels for 12 h; n = 7; data are expressed as mean ± SEM; *P<0.05, between the indicated groups. (B) JNK phosphorylation levels. InR1G cells were exposed to 11.1 mM glucose for 12 h, and stimulated using H₂O₂ (100 μM) for 5 or 15 min. (C) Akt phosphorylation and (D) glucagon secretion levels following the exposure of the cells to regular (11.1 mM) glucose levels in combination with (dotted)/without (white) 50 μM H₂O₂, or high (25 mM, black) glucose levels for 12 h, and the glucagon secretion was assessed after the stimulation with 25 mM glucose. Relative pAkt expression was determined using densitometry and normalized using total Akt levels; n = 4, each group. Data are expressed as mean ± SEM; *P<0.05, between the indicated groups.