Figure 7. Characterization of stress-induced erythropoiesis in Vhl^R/R mice.

(A) Hematocrit of Vhl^R/R mice, similar to that of WT mice, increased in response to PHZ (injected on days 1 and 2). However, the erythropoietic response was not downregulated appropriately in Vhl^R/R mice, and hematocrits continued to rise beyond WT levels to reach Vhl^R/R pre-PHZ levels. The result of 1 representative experiment is shown; similar results were obtained in separate experiments. (B) Spleen/body weight ratios in untreated mice and mice one month after PHZ injection; pooled results from multiple experiments are shown. Although the spleens of untreated Vhl^R/R mice were slightly larger (0.38% versus 0.3%), this difference was enhanced following PHZ, resulting in a greater increase in the size of mutant spleens compared with WT spleens.