(A) MCs were treated with 100 nM PTHrP (1–34) for indicated duration, and ERK1/2 phosphorylation was assessed by western blot (*P<0.05 vs control, n=3). (B) MCs were pretreated with Src inhibitor, PP1 or SU6656, prior to PTHrP (1–34) incubation for 1 h. ERK1/2 phosphorylation was assessed by western blot (*P<0.05 vs control, n=3). (C) MCs were pretreated with EGFR inhibitor, AG1478 or Gefitinib, before PTHrP (1–34) treatment for 1 h. ERK phosphorylation was assessed by western blot (*P<0.05 vs control, n=4). (D) MCs were pretreated with PI3K inhibitor, Wortmannin or LY294002, prior to PTHrP (1–34) treatment for 1 h. ERK1/2 phosphorylation was detected by western blot (*P<0.05 vs control, n=4).