Skeletal unloading alleviates the anabolic action of intermittent PTH(1-34) in mouse tibia in association with inhibition of PTH-induced increase in c-fos mRNA in bone marrow cells

We analyzed the effect of unloading by tail suspension on the anabolic action of intermittent PTH in the tibia of growing mice. Unloading alleviated the PTH-induced increase of bone formation and accelerated bone resorption, consequently reducing bone mass. Reduction of the PTH-induced anabolic actions on bone was associated with unloading, which was apparently related to suppression of c-fos mRNA expression in bone marrow.