A normobaric hypoxia facility for preparing polycythemic mice for assay of erythropoietin

A normobaric hypoxia chamber was designed in which large numbers of mice (up to 250) were made polycythemic, after which they were used in an erythropoietin assay. The hypoxic atmosphere was composed of air diluted with N2 gas generated from liquid N2. Continuous exposure of mice to 8% O2 for 11 da resulted in a polycythemia of sufficient magnitude and duration to provide appropriate erythropoietic conditions for the erythropoietin assay. The chamber, which has been in almost continuous operation for 3 yr, requires little attention and maintenance and has proved to be reliable, safe, and economical.