Fig. 1.

Initial rate of riboflavin (RF) uptake by pancreatic β-TC-6 cells as a function of substrate concentration. Cells were incubated at 37°C in Krebs-Ringer buffer (pH 7.4) in the presence of different concentrations of unlabeled RF, and uptake (5 min) by the saturable component was determined. Values are means ± SE of 3 independent experiments. When not visible, the error bars are smaller than the symbol.