Iron does not induce hepatic hepcidin gene expression in ActR2a^−/−;Bmpr2^fl/fl;Alb-Cre mice. (A) Male mice 10 to 12 weeks old with hepatocyte-specific deficiency of BMPR2 (Bmpr2^fl/fl;Alb-Cre, n = 8) and control mice (Bmpr2^fl/fl, n = 11) received an intravenous injection of dextran or iron-dextran (0.2 g/kg). After 4 hours, mice were sacrificed, livers were harvested, and RNA was extracted to measure hepcidin mRNA levels. ANOVAs P < .0001; *P < .0001 vs Bmpr2^fl/fl mice injected with dextran; ^#P < .0001 vs Bmpr2^fl/fl;Alb-Cre mice injected with dextran. (B) Male mice 10 to 12 weeks old globally deficient for ActR2a without or with hepatocyte-specific BMPR2 deficiency (ActR2a^−/−;Bmpr2^fl/fl [n = 10] and ActR2a^−/−;Bmpr2^fl/fl;Alb-Cre [n = 11], respectively) and control mice (ActR2a^+/+;Bmpr2^fl/fl [n = 8]) received an intravenous injection of dextran or iron-dextran (0.2 g/kg). After 4 hours, mice were sacrificed, livers were harvested, and RNA was extracted to measure hepcidin mRNA levels. Hepcidin mRNA levels in ActR2a^−/−;Bmpr2^fl/fl;Alb-Cre mice injected with dextran or iron-dextran are highlighted in an inset. ANOVAs P < .008; *P < .009 vs ActR2a^+/+;Bmpr2^fl/fl mice injected with dextran; ^#P < .008 vs ActR2a^−/−;Bmpr2^fl/fl mice injected with dextran; ^†P < .05 vs ActR2a^+/+;Bmpr2^fl/fl and ActR2a^−/−;Bmpr2^fl/fl mice, injected with dextran; ^††P < .001 vs ActR2a^+/+;Bmpr2^fl/fl and ActR2a^−/−;Bmpr2^fl/fl mice, challenged with iron-dextran.