Modulation of Erythropoietin Levels by Manipulation of Hypercarbia

摘要

The present studies were done in order to determine if preventing the respiratory alkalosis which is known to occur with acute ''hypoxic'' stimuli would lead to alterations in plasma levels of Ep. Rats were subjected to two acute stresses, hypoxia and acute blood loss, separately and in combination, with and without the added stress of hypercarbia. Hypercarbia in all experimental groups was associated with a decrease in plasma levels of Ep. This reduction in plasma Ep with hypercarbia could not be fully explained by the higher arterial PO sub 2 's or P50's of the hypercarbic rats. Hypercarbia may have indirectly suppressed Ep production by increasing blood flow to the site of Ep production. Alternatively, the cell of origin of EP could be sensitive to changes in pH and/or pCO sub 2 . It was further demonstrated that neither the onset nor the degree of reticulocytosis could be predicted by the plasma Ep levels. It is likely that the removal of red blood cells lead to a decrease in marrow transit time with the early emergence of reticulocytes after acute blood loss. (ERA citation 04:004459)