Dose-dependent suppression of hepcidin mRNA by rs-hemojuvelin in primary human hepatocyte culture. Primary human hepatocyte cultures (n = 5) from 4 different donors were treated for 24 hours with purified rs-hemojuvelin from 2 different preparations. Hepcidin mRNA was quantified by qRT-PCR and normalized to the housekeeping gene β-actin. For each experiment, the hepcidin-β-actin ratio of untreated cells was considered as a baseline of 1. Individual experiments (open symbols, dotted lines) and the regression line with 95% confidence intervals (solid line and dashed lines) are shown. Hepcidin mRNA expression showed a significant log-linear anticorrelation (R = -0.88, P < .001) with added rs-hemojuvelin concentration.