A urine concentrate of erythropoietin, obtained by chromatography on diethylamino‐ethyl (DEAE)‐cellulose, contained regulators of erythropoiesis that could be fractionated by selective membrane permeability. Two erythropoiesis stimulating factors (ESF) were obtained after exhaustive dialysis, one that diffused through the membrane and one in the retentate. A biochemical study of the ESF in the diffusate showed no appreciable sialic acid or fucose, a trace of hexosamine and a relatively small amount of protein. The remainder of the complex appeared to be an adrenocorticosteroid(s). The protein appeared to be a fragment of a glycoprotein. After exhaustive dialysis the retentate‐ESF had the characteristics of an ESF‐generating factor. The optimum pH for activity was about 7.4. It is suggested that an ESF(s) remains inactive when bound to a glycoprotein such as α1‐acid glycoprotein or the corticosteroid‐binding globulin. A role of an ESF‐generating factor would be to act on the complex to produce a fragment of the glycoprotein steroid complex, thereby activating the hormone.
|Original language||English (US)|
|Number of pages||10|
|Journal||Scandinavian Journal of Haematology|
|Publication status||Published - Jan 1 1971|
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