[High molecular substances in relation to disorders of erythropoiesis in patients in the terminal stage of chronic renal failure].

Fraction F1 with a MW of 5.10(3)-5.10(4), which had been isolated from the blood serum of blood donors as controls and patients at the terminal stage of chronic kidney insufficiency, specifically inhibited the erythropoiesis of test animals at the stage sensitive to erythropoietin and morphologically distinguishable cells of the bone-marrow.