In Vitro Production of Erythropoietin by Kidneys Perfused With a Serum-free Solution

Normal rabbits exposed to 0.4 atmospheric pressure for 3 hr will generate about 40-60 U of erythropoietin during a subsequent 3-hr period. If the kidneys were removed from 3-hr hypoxic animals, washed carefully, and perfused for 3 hr by recirculation with a serum-tissue culture mixture, each kidney generated about 14 U of erythropoietin in vitro. Perfusion of normal kidneys did not result in the production of erythropoietin, and only small amounts were generated if the perfusate contained Puromycin. Three-hour hypoxic kidneys perfused for 3 hr with a serum-free tissue culture medium were found to generate about 8 U of erythropoietin per kidney and similar kidneys perfused with saline about 1 U. These results indicate that erythropoietin is synthesized by kidney tissue and not produced by enzymatic activation of a plasma substrate.