TMPRSS6 expression is up-regulated in vivo by BMP6 and chronic iron treatment. (A) Eight-week-old male C57BL/6 mice received an intraperitoneal injection of BMP6 750 μg/kg animal weight (BMP6, black bars) or vehicle alone (mock, gray bars; n = 3 per group) for 6 and 12 hours. (B) Eight-week-old male C57BL/6 mice received an intraperitoneal injection of neutralizing BMP6 antibody 15 mg/kg once a day for 1 week (n = 5 per group). (C) Seven-week-old male C57BL/6 mice were killed at time zero (baseline) or after initiation of a 2% carbonyl iron diet for 24 hours, 48 hours, 72 hours, 1 week, or 2 weeks (n = 6 per group). Tissues were analyzed for hepatic hepcidin and Tmprss6 relative to Rpl19 mRNA by quantitative real-time RT-PCR. Results are reported as the mean ± SEM for the fold change from mock and significant changes represent the comparisons with mock. Significant changes are as follows: *P < .05; and ***P < .005.