Fig. 2.

Comparison of time-dependent efflux of ³H-Ch and F-Ch. (A) Efflux of ³H-Ch during a 24-h period. (B) Efflux of F-Ch during a 24-h period. Efflux shown in (A) and (B) was induced by addition of 10 μg/mL apoA-I and samples were collected at the indicated times. (C) Efflux of ³H-Ch during a 24-h period. (D) Efflux of F-Ch during a 24-h period. Efflux shown in (C) and (D) was induced by addition of 50 μg/mL HDL protein. All data were plotted by a nonlinear regression/curve fitting method. Asterisk (*) indicates a significant difference between BSA and cAMP treatment at the designated time. The data presented are mean ± SEM values of triplicate wells. The results are representative of 3 independent experiments. apoA-I, apolipoprotein A-I; BSA, bovine serum albumin; HDL, high-density lipoprotein; ³H-Ch, tritium-labeled cholesterol; SEM, standard error of the mean.