Role of Hemoglobin Affinity and Concentration in Determining Hypoxia Tolerance of Mammals During Infancy, Hypoxia, Hyperoxia and Irradiation

Abstract

The affinity of hemoglobin for oxygen is a major factor in determining the hypoxia tolerance of various species, and the increased hypoxia tolerance characteristic of infants and altitude-exposed animals. Modifications of affinity of hemoglobin, and probably hemoglobin type, occur in both young and adult animals of some species when exposed to alterations of O2 tension or irradiation. These modifications are not dependent upon splenic activity nor changes in oxygen capacity, but may be induced by intraperitoneal injection of serum from altitude-acclimatized rats. Maximal increases in tolerance are achieved only under optimal conditions of O2 tension, duration and frequency of exposure to hypoxia. No significant effect upon hypoxia tolerance due to alterations of O2 capacity could be demonstrated during growth, acclimatizations or blood loss and transfusion.