Figure 1. Effect of ET-1 on normal and asthmatic BASM proliferation.

(A) Normal BASM and (B) asthmatic BASM were grown to confluence and then growth-arrested for 24 hours in serum-free media with 0.1% BSA. Next, they were treated with EGF (10 nM), a positive control, ET-1 (0.001, 0.01, and 0.1 nM). As described in the Materials and Methods section, BrdU incorporation was measured after 18 hours of stimulation. DNA synthesis was compared with that obtained from cells treated with serum-free media (control). Data represent mean ± SEM from six to eight separate experiments. *Significance vs. control. ****P < 0.001.

BASM, bronchial airway smooth muscle; BrdU, 5-bromo-2’-deoxyuridine; BSA, bovine serum albumin; EGF, epidermal growth factor; ET-1, endothelin-1.