Figure 5.

IGF-IR tyrosine kinase inhibitor does not prevent GH-induced STAT5 activation. A and B, IGF-IR-floxed primary osteoblasts were serum starved and pretreated with vehicle or NVP-AEW-541 (5 mm, as indicated) for 16 h before stimulation with IGF-I (A, 100 ng/ml) or GH (B, 500 ng/ml) for 10 min. Detergent extracts were resolved by SDS-PAGE and immunoblotted with anti-pAkt and anti-Akt (A) or anti-pSTAT5 and anti-STAT5 (B). The blots shown are representative of two separate experiments. Note inhibition of IGF-I, but not GH, signaling by NVP-AEW-541.