Figure 1.

Effects of NGF on SCLC cell proliferation rate. Cells were exposed to 50 ng/ml NGF for different times. [³H]Thymidine incorporation was evaluated as described in Materials and Methods. The data are expressed as incorporated cpm/5 × 10⁵ cells. The complete time course of [³H]thymidine incorporation in NCI-N-592 cells is reported. (Inset) [³H]Thymidine incorporation in GLC8 cells. Points are the means ± SEM of three experiments, each performed in triplicate. *, P < 0.001 versus untreated cells by Student’s t test. Statistical analysis was applied to the points corresponding to individual times.