Hemojuvelin suppression decreased hepcidin expression but did not affect its inducibility by IL-6. Hep3B cells were first treated with hemojuvelin siRNA HJVsi3 (+) or diluent (-), followed by 20 ng/mL IL-6 () to induce hepcidin for 24 hours (n = 6 separate experiments). Hepcidin mRNAs were assayed by qRT-PCR and normalized to G3PD. In each experiment, expression of each target/G3PD ratio in control cells (not treated with IL-6 or siRNA) was set as the baseline of 1. Treatment with hemojuvelin siRNA significantly decreased both hemojuvelin and hepcidin mRNA levels in the presence and absence of IL-6, but did not affect mRNA expression of C/EBPδ. Significant differences as judged by the paired Student t test are indicated by their P values. Regardless of hemojuvelin siRNA treatment, IL-6 produced a similar fold induction of hepcidin and C/EBPδ mRNA expression, indicating that the IL-6 effect is not modulated by hemojuvelin expression.