Effects of leptin in combinations with various early-acting cytokines on the colony formation from 5 × 10⁴ BMC of 5-FU–treated mice. A total of 100 ng/mL of SCF and IL-11 and 10 ng/mL of IL-3, IL-4, IL-12, GM-CSF, LIF, and G-CSF were added in the presence (▨) or absence (▪) of 10³ ng/mL of leptin. Significantly different from their counterparts without leptin (*P < .05).