Fig. 2.

Effects of the differentiation stage of ARPE-19 cells on the cellular uptake of β-carotene [β-C (b-C)], LUT, and ZEA. Cells were plated on six-well plates to reach confluence after 7 days, the starting point of the experiment. At different points of differentiation (up to 10 weeks), cells were incubated with β-C, LUT, or ZEA at 1 μM for 18 h. After incubation, cells were analyzed for their carotenoid content. Values are expressed as picomoles of carotenoid per milligram of protein (A) or as percentage of carotenoid recovered in cells from the initial amount added to the cell culture media (B). Data are means ± SD of three independent experiments. * P < 0.05 compared with β-C at a given time point.