bGHTg Sca-1⁺c-Kit⁺Lin^–cells show altered CXCL12 function. (A) Sca-1⁺c-Kit⁺Lin^– cells from bGHTg and wt mice were allowed to migrate toward a CXCL12 gradient. The migration index was calculated as a percentage of input cells. Data represent the mean ± SD of quadruplicate determinations; *P ≤ .05. (B) Quantitative RT-PCR analysis of CXCR4, SOCS1, and SOCS3 mRNA from Sca-1⁺c-Kit⁺Lin^– cells isolated from bGHTg or wt mouse BM. Results are expressed as x-fold increase (“RT-PCR analysis”). The mean ± SD is shown for 6 independent experiments; **P ≤ .01. (C) Flow cytometry measurement of CXCR4 levels in Sca-1⁺c-Kit⁺Lin^– cells isolated from bGHTg or wt mouse BM. Histograms show representative experiments (n = 4). (D) Static adhesion of Sca-1⁺c-Kit⁺Lin^– cells from bGHTg and wt mice, undepleted or GH-depleted in vitro, on FN alone or with CXCL12. Results are expressed as a percentage of maximum adhered cells. Data represent the mean ± SD of quadruplicate determinations; *P ≤ .05.