The hematological response to hypoxia in growing guinea pigs is blunted during concomitant cold stress

Abstract

1. 1. Weanling male guinea pigs were exposed for up to 16 weeks to the combined stresses of cold (6 C) and hypoxia (ambient P o2 = 85 Torr). Hematological data for these animals and a group of adults maintained in the same environment for 4 weeks were compared to similar data for age and weight-matched controls raised at 22°C and P o2 = 133 Torr. 2. 2. During the initial 6 weeks of cold & hypoxia, hematocrit and [Hb] were elevated by 10–13°, above controls; these increases were accompanied by nonsignificant changes in #RBC's/mm 3, so that mild macrocytosis was evident. 3. 3. From week 6 onward, the hematological profile changed more dramatically, so that by week 16. the Hct, [Hb], and #RBC's were 31, 35 and 22% greater than controls respectively. 4. 4. Throughout the 16 weeks, polychromasia was slight and nucleated red cells were rare in the peripheral smears. 5. 5. These data for the weanling guinea pigs as well as those for the adult group indicate that particularly during the initial stages of exposure, concomitant cold stress appeared to blunt the erythropoietic response when compared to that reported earlier for a similar group of animals raised under a similar level of hypoxia but at 22°C.