Altered response to chemically induced anemia in Lyn^+/up adult mice. (A) Lyn^+/up mice respond the same as control animals to PHZ treatment induced splenomegaly. Spleen wet weight of Lyn^+/up and Lyn^+/+ adult mice (12-15 weeks) at 0, 3, and 5 days after PHZ treatment (n > 6, *P < .05). (B) Lyn^+/up hematocrits respond the same as control animals after PHZ induced red blood cell lysis. Analysis of the hematocrit in adult Lyn^+/up and Lyn^+/+ mice (12-15 weeks) at 0, 3, and 5 days after PHZ treatment (n > 6, *P < .05). (C) Extramedullary early erythroid progenitor (BFU-E) dynamics after PHZ treatment is similar in Lyn^+/up and control mice. Early erythroid colony assays (BFU-E) of spleens in Lyn^+/+ and Lyn^+/up adult mice (12-15 weeks) (n = 6, *P < .05). (D) Extramedullary late erythroid progenitor (CFU-E) dynamics after PHZ treatment is elevated in Lyn^+/up compared with control mice. Late erythroid colony assays (CFU-E) of spleens in Lyn^+/+ and Lyn^+/up adult mice (12-15 weeks) (n = 6, *P < .05). (E) Elevated maturing erythroid cells in the spleen of Lyn^+/up adult mice 3 days after PHZ treatment. Representative flow cytometric analysis of spleen cells from Lyn^+/+ and Lyn^+/up mice (12-15 weeks) at 3 days after PHZ treatment using anti-CD71 and anti-Ter119 and enumeration of the indicated erythroid subsets (R0, R1, R2, R3, R4; n > 6, *P < .05).⁴⁹  (F) Elevated maturing erythroid cells in the spleen of Lyn^+/up adult mice 5 days after PHZ treatment. Representative flow cytometric analysis of spleen cells from Lyn^+/+ and Lyn^+/up mice (12-15 weeks) at 5 days after PHZ treatment using anti-CD71 and anti-Ter119 and enumeration as in E (n > 6, *P < .05).