Induction of Vdr expression in BM and osteoblasts by β-AR stimulation. (A) BM was harvested from 7-week-old wild-type C57BL/6 mice 2 hours after PBS or isoprenaline administration (100 mg/kg, intraperitoneal), and expression levels were determined by real-time RT-PCR. Data were normalized to the expression level of β-actin. n = 6. NS, not significant. (B) BM was harvested from 7-week-old wild-type C57BL/6 mice at indicated times after the administration of single dose G-CSF (125 μg/kg, subcutaneously), and Vdr expression was determined by real-time RT-PCR. Data were normalized to β-actin expression. n = 5, 3, 4, 3, and 2 at 0, 2, 3, 4, and 6 hours, respectively. ** P < .01. (C-D) Differentiated MC3T3-E1 and primary carvarial osteoblasts were treated with 100μM pan-β adrenergic receptor agonist, isoprenaline (Iso), or β2-specific agonist, clenbuterol (Clen) for 2 hours, then harvested and processed for immunoblot analysis (C; a representative of 3 independent experiments is shown) and real-time PCR (D; n = 3).