THE HUMORAL REGULATION OF ERYTHROPOIESIS AND METABOLISM DURING RECOVERY FROM THE RAPID PRODUCTION OF ANAEMIA IN THE DOG

Abstract

The levels of erythropoietin and metabolic stimulating factor(s) were assayed in the plasma of dogs at 1 and 3 hours and at 2, 3, 4, 6–7, and 8–9 days after the rapid production of anaemia by dextran-for-blood exchange. The assay results were considered in relation to the reticulocyte response and oxygen consumption of the anaemic dogs over this same period.An increase in erythropoietin was first detected at 2 days and reached a maximum by 4 days after exchange. The level of erythropoietin was falling by 6–7 days and reached control levels by 8–9 days. An increase in reticulocyte level in anaemic dogs did not occur until 3–4 days and was maximal at 8–9 days.The metabolic stimulating activity of the plasma tended to parallel the changes in level of erythropoietin except at 3 hours when there was a considerable increase in metabolic activity although there was a normal level of erythropoietin. Protein-bound iodine in plasma was decreased following dextran-for-blood exchange. The oxygen consumption of the anaemic dog was below control levels at 1 and 3 hours, but subsequently above control levels at 4 to 9 days.The changes in erythropoietin and metabolic stimulating factor were somewhat similar to the change in level of a cardiotonic agent previously found in the blood of dogs during recovery from anaemia.