Fig. 5.

E2 does not modulate ErbB1 kinase activity in lactotrophs. A: GH3 cells were treated with E2 (0.01 nM), EGF (5 ng/ml), or their combination for 2 h, and equal amounts of cell lysates were subjected to Western blotting with anti c-Fos Ab (top) or anti-actin Ab (bottom). Data presented are from a single experiment and are representative of 2 separate experiments with similar results. B: GH3 cells transiently cotransfected with an AP-1 reporter gene and control reporter gene were treated with E2 (0.01 nM), EGF (5 ng/ml), or their combination, either alone or in presence of UO126 (10 μM) for 24 h, and normalized luciferase activity was determined as described in materials and methods. Data were calculated as fold change over control (arbitrary value of 1). Each value is the mean ± SE of 3 separate experiments, each performed in triplicates. *Significant difference from control; **significant difference from treatments without UO126 (P < 0.05).