rhGH injection triggers HSC mobilization in mice. (A) Mice received a daily injection of rhGH or PBS (7 days), and the clonogenic activity of BM cells was evaluated. The mean ± SD is shown for 3 independent experiments. The clonogenic activity of BM cells from bGHTg mice is included as a control. (B) Flow cytometry analysis of Sca-1⁺c-Kit⁺Lin^– cells in peripheral circulation of mice treated as in panel A. As control, Sca-1⁺c-Kit⁺Lin^– staining is shown for bGHTg mouse blood. The mean ± SD is shown for 7 independent experiments. (C) Flow cytometry of myeloid lineages (Gr1, CD11b) in the right (left panels) and left (right panels) femurs of mice reconstituted by injection in the right femur with whole blood from mice treated for 7 days with rhGH or PBS. Values (inset) represent the percentage of positive cells. Histograms show representative animals (n = 8). (D) T (CD4, CD8) and B-cell (B220) population analysis in peripheral blood of mice reconstituted as in panel C. Values represent the percentage of positive cells. Histograms correspond to representative animals (n = 8).