Figure 2.

[¹⁴C]choline incorporation into [¹⁴C]PtdCho increases in PC12 cells stimulated with NGF or bFGF. (A) PC12 cells that had been treated with or without NGF (50 ng/ml) or bFGF (50 ng/ml) for 2 or 4 days were labeled with [methyl-¹⁴C]choline for 2 hr, and [¹⁴C]choline incorporation into [¹⁴C]PtdCho was determined. (B) [¹⁴C]choline incorporation was analyzed in PC12 cells treated with the indicated concentrations of NGF for 4 days. Results are means ± SEM from three independent experiments; duplicate dishes were used for each treatment. ∗, P < 0.05; ∗∗, P < 0.01 compared with control. C, control.