Figure 1.

Phosphorylation of AMPK, IRE1α protein expression, phosphorylation of PERK, and GRP78/BiP protein expression in the presence or absence of melatonin and/or 2-DG in rat insulinoma INS-1E cells. INS-1E cells were incubated in RPMI 1640 medium supplemented with 2% FBS with/without melatonin (100 μM) and/or 2-DG (5 mM) for 24 hr at 37°C with 5% CO₂. p-AMPK expression was analyzed by Western blot (a, c). The relative amount of p-AMPK (b), IRE1α protein (d), p-PERK (e), and GRP78/BiP protein (f) was quantified as described in Section 2. Data represent mean ± SD of three experiments (n = 3). ^∗ p < 0.05, ^∗∗ p < 0.01, and ^∗∗∗ p < 0.001 versus 2% FBS; ^## p < 0.01, ^### p < 0.001, melatonin versus melatonin and/or 2-DG.