The existence of activin A / erythroid differentiation factor and its inhibitor in human serum: Comparison of normal and chronic renal failure sera

Abstract

Activin A EDF , initially found as a differentiation inducer of murine Friend erythroleukemia, also has a stimulatory effect on erythropoiesis in vitro and in vivo . Here we proved activin A EDF activity in human serum. The activin A EDF level in 18 normal human serum samples was measured by a specific bioassay and was found to be 8.3 ± 4.6 ng/ml, indicating that there exists sufficient activity to affect erythropoiesis in normal serum. In contrast, activin A EDF activity was reduced in the chronic renal failure patients and 23 26 serum samples examined showed levels below 1.2 ng/ml. Further analysis using HPLC revealed that chronic renal failure serum actually contained as much activin A EDF as normal serum, and that the difference between normal and patient serum existed in the content of a specific inhibitor of activin A EDF . This observation suggests the possibility that the inhibitor is participating in the regulation of activin A EDF activity in vivo in chronic renal failure patients and also the possibility of activin A EDF could be utilized in the therapy of the anemia of such patients.