ERYTHROPOIETIN AND THE HUMAN KIDNEY - EVIDENCE FOR AN EVOLUTIONARY LINK FROM STUDIES OF SALMO-GAIRDNERI

1. Ultrastructural evidence is provided of renal erythropoiesis in Salmo gairdneri. 2. Supernatants prepared from homogenates of the kidney of this teleost contain more immunoreactive erythropoietin than autologous plasma or serum or supernatants prepared from homogenates of spleen or liver. Thus, the trout kidney is not only a major erythropoietic organ but also a major source of erythropoietin. 3. These data provide the first immunochemical demonstration of the production of erythropoietin in fish and indicate that locally generated erythropoietin may be important in the regulation of renal erythropoiesis in the trout. 4. The results also suggest that the role of the kidney in the regulation of bone marrow erythropoiesis in humans may have an evolutionary basis.