Fig. 7. Activation of K-Ras by OSM in fetal hepatocytes. Serum-starved fetal hepatocytes were stimulated with 10 ng/ml of OSM for 15 or 30 min before cell lysis. Cell lysates were subjected to affinity precipitation with GST–RBD. Protein levels of GTP-bound K-Ras and total K-Ras were determined by western blotting using a K-Ras-specific antibody. GST was used as a negative control.