Fig. 6. IGF-I-stimulated MAPK activation in the presence of PT. Proliferating 3T3-L1 cells were treated with 200 ng/ml PT for 16 h prior to stimulation with (solid bars) or without (open bars) 10 nM IGF-I for 5 min. Proteins in cell lysates were separated by SDS-PAGE and analyzed by Western blotting using phospho-MAPK antibodies (P-MAPK) followed by ERK1/2 MAPK antibodies (Total MAPK). The corresponding densitometry of the blots is expressed as mean + SE of phospho-MAPK corrected for total MAPK.