Alk2 and Alk3 are required for BMP2-mediated induction of hepcidin gene expression and loss of Alk3 suppresses basal hepcidin mRNA levels in isolated hepatocytes. Isolated hepatocytes were treated with and without BMP2 (100 ng/mL) for 2 hours (n = 5 hepatocyte isolations from Alk2^fl/fl mice; n = 3 hepatocyte isolations from Alk2^fl/fl; Alb-Cre, Alk3^fl/fl and Alk3^fl/fl; Alb-Cre mice, each). (A) Hepcidin mRNA levels in Alk2^fl/fl and Alk2^fl/fl; Alb-Cre hepatocytes. *P = .0075, Alk2^fl/fl without versus with BMP2. (B) Hepcidin mRNA levels in similarly treated Alk3^fl/fl and Alk3^fl/fl; Alb-Cre hepatocytes. *P < .05, Alk3^fl/fl without versus with BMP2. ^#P < .0001 Alk3^fl/fl; Alb-Cre without BMP2 versus Alk3^fl/fl without BMP2.