Delayed induction of Hbb-LCR-luc compared with G1-HRD-luc in response to anemia. (A) Bioluminescent images of G1-HRD-luc (top panels) and Hbb-LCR-luc (bottom panels) mice after 4 serial blood deprivations with 12-hour intervals. The day 0 image was taken before phlebotomy. (B) Average change in photon output from areas including the spleen of G1-HRD-luc (▴) and Hbb-LCR-luc (⋄) mice. Four to 6 mice were examined in each group. The intensity of the bioluminescent signal of day 0 was set to 1. Error bars indicate SD. *P < .05 compared with day 0. (C) EPO concentrations in the plasma of G1-HRD-luc (▦) and Hbb-LCR-luc mice (□) on the first and fourth blood deprivation (n = 6 in each group). Error bars indicate SD.