Carbon monoxide and erythropoietin production in mice

The effects of hypoxemia caused by hypoxia (H-H) and CO (H-CO) on the production of erythropoietin (ESF) in mice were investigated. When mice breathed for 6 hr mixtures of air containing 0.1% of CO or a mixture of air and nitrogen with a pO2 of 52 mm Hg, the tissue pO2 as measured by the gas pocket technique was 16.9 +/- 1.1 and 17.1 +/- 1.4 (mean +/- S.D.), respectively. Plasma ESF content in H-CO mice, however, was twice higher than in the H-H mice. The greater ESF production in H-CO was associated to a significantly less hyperventilatory response as measured by acid-base balance changes and to a lower O2 consumption and was interpreted as the result of displacement of the OHb curve in opposite directions. The ESF organ appears thus to be sensitive to variations in the amount of O2 delivered to the tissues but independent of the arterial pO2.