Abstract
The effects of ESF on uptake of C14-labeled amino acids and Fe59 into hemoglobin and on reticulocyte levels of normal mice were studied as a function of time after single intravenous injection. The first change observed was a marked increase of C14 amino acid uptake into hemoglobin at 24 hours, followed by increased Fe59 consumption by erythroid tissue at 48 hours, and an increased reticulocyte count in the peripheral blood at 72 hours.