Erythropoietin–hematocrit feedback circuit in the anemia of end–stage renal disease

Erythropoietin–hematocrit feedback circuit in the anemia of end–stage renal disease. Deficient erythropoietin (EP) production is thought to be a key factor in the pathogenesis of the anemia of end-stage renal disease. We describe the interrelationships between radioimmunoas-sayed plasma EP levels, reticulocyte counts corrected for anemia (CRC) and hematocrit (HCT) under challenge by hemorrhage, transfusions and hemodialysis in 32 chronically–hemodialyzed patients. Spontaneous hemorrhage resulted in a decrease in HCT (P = 0.001) and increases in both EP (P = 0.006) and CRC levels (P = 0.0065). Transfusions of two units of packed red cells into each of 16 patients suppressed EP (P = 0.0004) and CRC (P