The Influence of Anoxia of Lactating Rats and Mice on Blood of Their Normal Offspring

1) Lactating rats and mice 3 to 4 days post partum were discontinuously exposed daily to an ambient pressure of 400 to 300 mm. Hg for 6 hours while their litters remained at sea level pressure. At the same time, control rats and mice were separated from their litters but were kept at sea level pressure.

2) When baby rats were sampled from 10 to 25 days of age, the hematocrits, erythrocyte counts and O₂ capacity values of those nursed by anoxic mothers were greater than those nursed by the normal mothers. The total hemoglobin content of baby mice nursed by anoxic mothers generally exceeded those obtained from mice nursed by normal mothers.

3) The evidence indicates that a substance is present in the milk of anoxic rats and mice which produces an increased hemoglobin content of the nursing young.