Figure 2. Effects of LPA on ³[H]-thymidine incorporation of DPF. (A) Dose-response curve of the indicated concentrations of LPA on ³[H]-thymidine incorporation of DPF. The Fig. shows the mean and standard deviation of results from 6 independent preparations, each performed in quadruplicate. *P < 0.05 and **P < 0.01 vs. unstimulated cells. (B) Effects of inhibitors of MAPK signaling U0126, SB203580, and SP600125 on ³[H]-thymidine incorporation by DPF of 6 individual preparations. Results are shown as mean and standard deviation. *P < 0.05 and **P < 0.01 vs. LPA alone. (C) Staining pattern of the nuclear antigen Ki67 in DPF incubated for 24 hrs with and without LPA at 10 µM. (D) Relative number of Ki67-positive cells in the indicated cultures. Data are means and standard deviation of results from triplicates of one donor. *P < 0.05.