(A) (B) Elevation of intracellular cGMP levels in sGC-5 mouse peripheral RBCs (A) and leukocytes (B). Intracellular cGMP levels of blood cells were measured using ELISA kits, as described in S1 Text. P values: *, P<0.01 compared with Tg(-) littermates. (C) (D) The sGC activity of spleen-derived erythroblasts and peripheral leukocytes are elevated in sGC mice. Cellular extracts prepared from erythroblasts or leukocytes were incubated with or without sodium nitroprusside (SNP; 0.1 or 5 μM) and sGC activity was determined by measuring the cGMP levels in the mixtures. P value: *, P<0.01 compared with Tg(-) littermates. (E) (F) Cellular extracts were subjected to immunoblotting to examine VASP phosphorylation in spleen-derived erythroblasts and peripheral leukocytes of sGC transgenic and Tg(-) mice. The experiment was repeated 3 times and a representative result is shown. Protein band intensity was quantified by the NIH image software Image J (version 1.63) and the results are summarized in Fig 2F. P value: *, P<0.01 compared with Tg(-) littermates. (G-J) Complete blood counts of sGC mice. RBCs (G), total hemoglobin (H), hematocrit (I), and leukocyte count (J) of sGC-5, sGC-7, and non-transgenic littermates were analyzed. See S2 Table for other hematologic values. P value: *, P < .05 compared with Tg(-) non-transgenic littermates.