Figure 3.

The effect of metals on ERK1/2 phosphorylation in thyrospheres. Thyrospheres were treated for 30 min with the indicated metals at the concentrations causing maximum BrdU incorporation, lysed at the indicated times and analyzed for ERK1/2 phosphorylation by Western blot. (A) Representative immunoblots from six separate experiments. (B) Histograms represent the mean value ± SEM of densitometric values normalized to vinculin and expressed as percent of time 0. *p < 0.05, **p < 0.01, ***p < 0.001.