Characterization of mice carrying the inducible hepcidin transgenes crossed with Hfe^-/- mice after treatment for 3 weeks with doxycycline. In this figure, each column represents the same animal. (A) Hepcidin mRNA levels in the livers of control (cont), Hfe^-/- and inducible/Hfe^-/- mice (ind/Hfe^-/, ie, mice harboring both tetO-Hepc1 and rTA^LAP-1 transgenes and with Hfe^-/- genotype) treated for 3 weeks with doxycycline. Total liver RNA (20 μg) was fractionated by electrophoresis, blotted, and hybridized with hepcidin and 18S-labeled probes. (B) Ferritin and ferroportin levels as assessed by immunoblot analysis of livers and spleens of control, Hfe^-/- and ind/Hfe^-/- mice treated for 3 weeks with doxycycline. Anti-mouse L-ferritin antibody was used to probe 20 μg hepatic (top panel) or splenic (bottom panel) cytosolic extract. Anti-mouse ferroportin antibody was used to probe 50 μg hepatic (top panel) or 20 μg splenic (bottom panel) microsomal extract. Molecular weight markers (kDa) are indicated on the left. The levels of serum iron and liver iron are shown for each animal.