Effect of SB202190 on the GnRH-I- or GnRH-II-induced inhibition of cell growth. HEC1A cells were treated with GnRH-I or GnRH-II for 24 h in serum-free medium in the absence or presence of SB202190 (100 nM), a specific inhibitor of p38. Cell proliferation was determined by 3H-thymidin incorporation assay following treatment with GnRHs. Values are the mean cell number (± S.E.) from three independent experiments. Values are the means of cell number (± S.E.) in triplicates of three independent experiments. a, indicates p < 0.05 vs. control (cont); b, indicates p < 0.05 vs. GnRH-I or GnRH-II treatment only.