Figure 2.
Progestin regulation of NPC proliferation. Rat NPCs were starved for 4 h before exposure to clinical progestins (10 × e−12 to 10 × e−5 m) for 24 h. Cell proliferation was evaluated by BrdU chemiluminescence ELISA measuring BrdU incorporation. Ethanol was used as vehicle control (1 × e−6), and bFGF was used as positive control. At each concentration, the proliferative efficacies of progestins (solid lines) were compared against that of P4 (dotted line). A–C, Effects of progestins that had greater proliferative efficacy relative to P4. D and E, Progestins with lower proliferative efficacy relative to P4. F–H, Progestins with no or antagonizing effects on cell proliferation. Data are derived from three independent assays, analyzed using one-way ANOVA, followed by Neuman-Keuls post hoc test, and plotted as percentage increase vs. vehicle control (mean ± sem). *, P < 0.05; **, P < 0.01; ***, P < 0.005; and ****, P < 0.001 vs. vehicle control.