Extraction from fetal bovine serum of erythrotropin, an erythroid cell-stimulating factor.

A method is described for the rapid preparation of erythrotropin from commercially available fetal bovine serum. It consists of the reversed-phase extraction of fetal bovine serum using octadecylsilyl-silica cartridges followed by reversed-phase high-pressure liquid chromatography (HPLC). Further purification can be achieved by gel-permeation HPLC. Serum erythrotropin coelutes with erythrotropin I from fetal bovine intestine on reversed-phase HPLC. It has a molecular weight and an amino acid composition very similar to those reported for the intestinal erythrotropins. The easy preparation of serum erythrotropin with specific activities higher than commercially available erythropoietin preparations will facilitate the study of the physiological role of this factor in vivo and in vitro.