FIG. 5.

Osteogenic phenotype of human mesenchymal stem cells. MSCs were cultured in growth medium (GM) or osteogenic medium (OST) for 14 days. MSCs were treated with fresh medium for 24 h. Alkaline phosphatase specific activity (A) was measured in the cell lysates. Levels of secreted osteocalcin (B) and osteoprotegerin (C) were measured in the conditioned medium. *P<0.05, versus control;*P<0.05, versus GM. To assess rapid, membrane-initiated signaling, protein kinase C activity was measured after 9 min treatment with 0.01% ethanol or 1α,25(OH)₂D₃ (D). *P<0.05, versus control; ^#P<0.05, versus 1α,25(OH)₂D₃.