[Glucocorticoid and Bone. The effect of glucocorticoid and PTH in osteoblast apoptosis and differentiation via interleukin 11 expression].

Intermittent PTH administration stimulates bone formation and counteracts the inhibition of bone formation by glucocorticoid excess. We have previously demonstrated that PTH enhances interleukin (IL) -11 gene transcription by a rapid induction of delta-fosB expression and Smad1/5 phosphorylation. On the other hand, glucocorticoid can suppress osteoblast differentiation and enhance apoptosis of osteoblast cells via down-regulation of IL-11 expression. PTH could reverse glucocorticoid-induced these damage of osteoblast via stimulation of IL-11 expression. Our data also suggested that IL-11 mediates stimulatory and inhibitory signals of osteoblast differentiation by affecting Wnt signaling. These data demonstrates that PTH and glucocorticoid may regulate osteoblast differentiation and apoptosis via their effect on IL-11 expression.