Cellular zinc accumulation in RWPE1 and RWPE2. a. Total cell-associated zinc contents. RWPE1 and RWPE2 were grown to ~50% confluence and treated with 0 or 75 μM ZnSO4 at 37°C for 48 hours. Cells were harvested and assayed for total cell-associated zinc contents by inductively coupled plasma-atomic emission spectrometry. Values are the means ± SE, n = 3 (three independent experiments). b. 65Zn accumulation. RWPE1 and RWPE2 were grown to ~70% confluence and harvested. Zinc accumulation was assayed with 0.05 μM 65ZnCl2 from 0 to 60 minutes. Values are the means ± SE, n = 3 (one representative experiment of three with similar results).