Protein Metabolism and Erythropoiesis. I. The Anemia of Protein Deprivation

(1) Protein deprivation in rats resulted in a rapid depression of iron incorporation. The depression reached its maximum within 6 days. Realimentation with protein was followed within 3 days by a return of iron incorporation to normal values.

(2) Red cell mass declined during protein starvation in a linear fashion, indicating a removal of senescent red cells after a life span of 70 days. The increasing severity of the anemia of protein starvation is the cumulative result of this removal in the absence of any significant replacement.

(3) Daily injections of 1.3 units of erythropoietin prevented a decrease in red cell mass over an observation period of 28 days of protein starvation.

(4) Diminished erythropoietin formation or retardation of protein synthesis in erythroid precursors due to lowered substrate concentration are considered as possible causes of erythropoietic depression.