Effects of the length of incubation of cell cultures with genistein on inhibition of EFG receptor phosphorylation. Experiments were performed as described in Methods and in captions to Figs. 3 and 4. Genistein was used at final concentrations of 10 μM (black columns) or 30 μM (grey columns). Results of experiments with HDFa (panel A) and MPS II (panel B) fibroblasts are shown. Other tested fibroblasts gave similar results (results not shown). Values represent mean ± range of duplicate determinations.