Presence of erythropoietic factor in plasma of normal and hypophysectomized rats following bleeding.

Abstract

Summary1. Normal adult-female rats were injected intravenously with a total of 6 or 9 cc of plasma, over a 3-day period, obtained from normal rats, bled normal rats, hypophysectomized rats, or bled hypophysectomized rats. Reticulocyte response was used as criterion of erythropoietic activity and blood was removed for reticulocyte counts 24 and 48 hours after the last plasma injection. 2. Best results were obtained with the larger dose level. Erythropoietic factor was present in the plasma of the bled normal rats, the reticulocyte count being elevated 483% above normal. The plasma factor was also found to be present in bled hypophysectomized rats, the reticulocyte count of the recipient rats being elevated 138% above normal levels. This factor was also found in the plasma of unbled hypophysectomized rats, a fact which needs further investigation.Conclusions. This experiment indicates that erythropoietic factor can be demonstrated in normal bled rats and that hypophysectomy does not prevent its formation.