FIG. 1.

Proliferative effects of HRG require PR and p42/p44 MAPK activation. C4HD (A) and T47D (B) cells were incubated for 48 h in medium with ChFCS supplemented, as indicated, with RU486, 10 nM MPA, MPA-RU486, HRG, HRG-RU486, HRG-ASODN or -SODN plus ErbB-2, or HRG-PD98059. C4HD cells were also treated with HRG plus increasing concentrations (1, 5, and 10 μg/ml) of either ErbB-3 monoclonal antibody (Ab-5) or ErbB-4 monoclonal antibody (Ab-3) and HRG plus preimmune mouse serum (NMS). Incorporation of [³H]thymidine was used as a measure of DNA synthesis. Data are presented as means ± the standard deviation (SD). Significance for columns b versus a, columns c versus b, columns d versus a, and columns e versus d, P < 0.001. The experiments shown are representative of a total of five for each cell type.