αTC1.6 cells were seeded into a 96-well plate (Greiner, Frickenhausen, Germany) at a density of 2.0 × 104 cells per well and were then preincubated in KRB containing 20 mM glucose, 5 μM fluo-4/AM, 5 mM probenecid, and 1× Power load (all from Invitrogen) for 30 min at 37 ...