AMD3100-induced changes in CXCL12 gradient coincided with and mediated mobilization of leukocytes and HPCs. (A-D) Mice were administered AMD3100 (5 mg/kg mouse IP) or vehicle (dash), and at varying time points (1, 2, and 4 hours), blood was collected for analysis of circulating total nucleated cells (TNCs) (A) and CFU-HPCs (B) (n = 11-14 mice per group). Femoral bone marrow and peripheral blood were collected for quantification of CXCL12 in bone marrow (BM) supernatant (C) and PB plasma (D), respectively (n = 7-14 mice per group). CXCL12 levels are shown as picograms per milliliter. Data of at least 3 independent experiments are represented as mean ± SEM. *P < .05; **P < .01; ***P < .001 (one-way ANOVA with Dunnett test). (E-F) Mice were administered AMD3100 or vehicle (dash) in the presence or absence of the CXCL12 neutraligand chalcone 4-phosphate (C4P; 1.5 µmol/kg mouse IV), and 1 hour later, blood was collected for analysis of circulating TNCs (E) and CFU-HPCs (F) (n = 5-10 mice per group). TNCs and CFU-HPCs are shown as cells and colonies per milliliter of blood, respectively. Data from at least 2 independent experiments are represented as mean ± SEM. **P < .01; ***P < .001 (one-way ANOVA with Bonferroni test). NL, neutraligand; ns, not significant.