Erythroid phenotypes of V205GR adult mice. (A) Red cell parameters of adult V205GR mice. Three V205GR-B and 3 WT mice were used. (*P < .05, **P < .01, ***P < .005). (B) Plasma erythropoietin concentration was significantly elevated in V205GR-B mice. Nine WT (open bars) and 8 V205GR-B (filled bars) mice at the age of 4 to 12 months were used. (C) Spleen of a 6-month-old V205GR-B mouse was markedly enlarged. Scale bars correspond to 5.0 mm. (D) Histologic examination of spleens of V205GR-B (bottom panel) and WT littermate (top panel) shown in panel C. High magnitude image of red pulp area is shown in insets. Note that a large number of enucleated mature erythrocytes are observed in the enlarged red pulp area of V205GR-B spleen. Scale bars correspond to 0.5 mm and 20 μm. (E) Mature erythroid population (c-Kit⁻CD71⁺TER119⁺) was increased in the spleen of V205GR-B (bottom panel) compared with WT littermate (top panel). The frequencies and mean intensity values of TER119⁺ cells are shown in the panels. (F) Changes of hematocrit values taken from 3 V205GR-B (black lines) and 3 WT (gray lines) mice after exposure to a low dose of phenylhydrazine. (G) Yellowish plasma was observed in V205GR-B mice after phenylhydrazine treatment.