Early erythropoietin, blood, and physiological responses to severe hypoxia in man.

Abstract

Serum and urinary erythropoietin, plasma-Fe turnover, and various physiological parameters were systematically measured in a human subject exposed 4 days to 405.6 mm Hg (simulated 16,400 ft) following rapid decompression. Serum erythropoietin became detectable at 12 hr, reached maximum concentration on the 3rd day, and fell to low levels on the 4th. Plasma-Fe turnover and hemoglobin synthesis followed a similar pattern, although elevated rates persisted for some time after return to sea-level pressure. The rise and fall in serum erythropoietin correlated with other physiological changes occurring during acute acclimatization, including marked changes in cardiac and pulmonary function, subsidence of severe hypoxic symptoms, and increased serum protein-bound iodine, oxygen consumption, urinary excretion of adreno-cortical steroids, and concentration of all blood cells except erythrocytes in peripheral blood. No significant changes occurred in total red cell and plasma volumes nor in the measured blood and urinary electrolyte and enzyme concentrations.