GBT1118, a potent allosteric modifier of hemoglobin O affinity, increases tolerance to severe hypoxia in mice.

Adaptation to hypoxia requires compensatory mechanisms that affect O transport and utilization. Decreased hemoglobin (Hb) O affinity is considered part of the physiological adaptive process to chronic hypoxia. However, this study explores the hypothesis that increased Hb O affinity can complement acute physiological responses to hypoxia by increasing O uptake and delivery compared with normal Hb O affinity during acute severe hypoxia.