Figure 3

Effect of PE, cAMP-elevating agents and EGF on protein and DNA synthesis. A, Cells were treated with 5 μM PE, 1 μM forskolin (FN) and 30 ng/ml EGF for different periods. [³H]leucine incorporation was measured as described in Methods. Data are expressed as dpm of [³H]leucine incorporated per well. Values are the mean ± S.E. of three independent experiments performed in sextuplicates. * Values significantly different from vehicle, p < .05. B, Effect of FN, 8-cpt-cAMP and PE on EGF-induced [³H]thymidine incorporation. Cells were preincubated with FN (1 μM), 8-cpt-cAMP (5 μM) and PE (5 μM) for 1 h. Cells were then treated with EGF (30 ng/ml) for 18 h. Incorporation of [³H]thymidine into rat-1 fibroblasts was determined as described in Methods. Data are expressed as dpm of [³H]thymidine incorporated per well. Values are the mean ± S.E. of three independent experiments performed in duplicate in different batches of cells. * Value significantly different from vehicle, p < .05. § Value significantly different from the corresponding value obtained without treatment by FN, cpt-cAMP or PE, p < .05.