Limited contribution of HSCs to recovery from blood loss. (A-E) Fgd5^{ZsGreen:CreERT2}/R26^LSL-tdRFP (in panels A-D, n = 6-7 per condition) and R26^rtTA/Col1A1^H2B-GFP (in panel E, n = 6-7 per condition) mice were IP injected with phenylhydrazine (PHZ) or PBS. Hematocrit (HCT) 24 hours after PHZ application (B) and PB RBC numbers (C) are shown. (D) Fraction of RFP-labeled cells (relative to ES HSCs). (E) Average number of additional divisions in response to PHZ. (F-L) Fgd5^{ZsGreen:CreERT2}/R26^LSL-tdRFP (in panels F-K, n = 4-8 per condition) and R26^rtTA/Col1A1^H2B-GFP (in panel L, n = 4-8 per condition) mice were treated with antiplatelet (αPlt) serum or control serum following a single (once in panels F-G, J, and L) or repetitive (7 times in panels H-I and K-L) application protocol. (G-I) Platelet numbers in PB. (J-K) Fraction of RFP-labeled cells (relative to ES HSCs). (L) Average number of additional divisions in response to platelet depletion. (M) Net effects of RBC or platelet depletion on RFP label propagation (% label increase relative to ES HSCs; transformation and display of data as in Figure 1P).