Loss of bone marrow osteoblasts is associated with cytokine-induced mobilization. Mice (n = 4-6 each group) were treated with G-CSF, Flt3L, or SCF for 7 days. Bone marrow osteoblasts were enumerated in H&E-stained paraffin sections using standard histomorphometric technique. Shown is the percentage of osteoblast-covered bone surface (A) and number of osteoblasts per bone perimeter (B). Data represent mean ± SEM; *P < .05.