[Effect of salbutamol on proliferation of human bronchial epithelial cells: role of MAP kinase].

To determine whether stimulation of beta-adrenoceptors affects proliferation of airway epithelial cells and, if so, whether activation of mitogen-activated protein kinase (MAPK) is involved, we studied cultured human bronchial epithelial (16-HBE) cells in vitro. The 16-HBE cells were grown to subconfluence in 96-well plates, and their growth was inhibited by incubation in serum-free medium for 72 h. The cells were ten incubated in the presence of saltbutamol (SAL, 10(-7) M), a specific beta(2)-adrenoceptor agonist. Proliferation of the cells was evaluated by MTT assay and total DNA content, and activation of MAPK was assessed by immunocytochemistry and Western blotting for phosphorylated MAPK (phospho-MAPK). Immunocytochemistry and immunoblots demonstrated that phospho-MAPK was expressed within minutes of SAL exposure. This effect of SAL was as potent as that of 10% serum, and was greatly inhibited by treatment with propranolol. These results suggest that SAL is a potent mitogen of airway epithelial cells and that its effect may be exerted by beta(2)-adrenocepter-mediated activation of MAPK.