Time course of Akt phosphorylation in response to IGF-1 in TSHR+/+ and TSHR−/− fibroblasts. Fibroblasts were grown to confluence and treated as described in Materials and Methods with IGF-1 (100 ng/mL) for the times indicated along the abscissas. Monolayers were collected and subjected to Western blot analysis for pAkt. Densities were corrected for their β-actin controls. Relative densities were as follows: time 0, TSHR+/+ 0.23, TSHR−/− 0.22; time 5 minutes, TSHR+/+ 0.70, TSHR−/− 1.62; 15 minutes, TSHR+/+ 0.61, TSHR−/− 1.46; and 30 minutes, TSHR+/+ 0.86, TSHR−/− 2.50.