Figure 3.

Hypoxanthine levels decrease in human and mouse red blood cells exposed to hypoxia in vivo and in vitro. (A) RBC were collected from 21 healthy volunteers at sea level (SL) and within 3 or >8 h after exposure to high altitude hypoxia on day 1 (ALT1 am and pm, respectively), and at 7 days (ALT7) after exposure to high altitude (>5000 m) hypoxia. (B) Hypoxanthine levels decreased significantly in human RBC within hours of exposure to high altitude hypoxia (x axis labels consistent with description of panel A). (C) C57BL/6J mice (n=6) were exposed to normoxia or 8% oxygen for 3 h, resulting in decreases in RBC levels of hypoxanthine, a phenomenon accompanied by decreased IMP and increased AMP/IMP ratios (Online Supplementary Figure S1). (D) RBC were collected from C57BL/6J mice prior to in vitro storage in AS-3 for up to 2 weeks under normoxic or hypoxic conditions, resulting in decreased hypoxanthine accumulation.