Erythropoietic Activity in Plasma and Urine of Dogs After Bleeding.

Abstract

Bled dogs provide a source of erythropoietically active plasma and urine to serve for both biological and chemical investigation. From 6 dogs which were bled until hematocrit values of 5-11% were reached, boiled filtrates of plasma were prepared, while urine was frozen and assayed without further treatment. Erythropoietic activity was measured by Fe59 red cell incorporation assay using starved female rats of Long-Evans strain. The erythropoietic activity of plasma obtained at different degrees of anemia was compared to that of normal plasma. When the hematocrit was above 16% there was no activity. The highest activity in urine and plasma was found with hematocrits of 9% or less. Plasma retained activity after 24 hours at room temperature, but lost some activity after boiling. Erythropoietic activity of plasma and urine decreased after long storage in the frozen state.