Abstract
Kinetics of eosinophil granulocytes have been studied in guinea pigs simultaneously exposed to severe at imulated aitude of 20,000 ft(6,096 m) by determining the percentages of blood eosi- showing DNA-labelling at intervals after an Hypoxia 8-hour course of tritiated thymidine injections. Labelled eosinophils were detected at an earlier interval in hypoxic animals (36 h against 72 h in the controls) and a higher percentage-labelling was found up to and including 108 h. Thereafter, percentage-labelling was generally similar to that of the controls. The results are taken to indicate a reduction in transit time across the postmitotic marrow eosinophil pool and to be consistent with an increased rate of release of these cells into the circulation.