The Role of the Kidney in Erythropoiesis*

The pathogenesis of anemia in chronic and acute renal insufficiency has not yet been fully understood. Emerson and Burrows (1) and Chaplin and Mollison (2), using the Ashby tech- nic, have shown the decreased red cell survival in chronic and acute nephritis. Later other workers (3-6) noted the same defect, and Muirhead and co-workers (7, 8) studying nephrectomized rab- bits and dogs pointed out a hemolytic picture. Loge, Lange and Moore (9) in 1950, using radio- active iron, observed a reduced uptake in the red cells of uremic patients; these findings were con- firmed by others using Fe59 with high specificity (4-6, 10). This reduction of the erythropoietic function was also demonstrated by the depletion of erythroblasts from the marrow in uremic pa- tients (6, 11, 12) and by the severe erythroblasto- penia commonly associated with acute renal failure (6, 13). These observations show that uremic anemia results from a double mechanism: a short red cell survival and a depression of erythropoiesis.