The Action and Neutralization of a Renal Lipid Inhibitor of Erythropoietin

Abstract

SummaryA potent inhibitor of erythropoietin was isolated from rabbit renal homog-enates and found to be soluble in ether and acetone. It contained primarily neutral lipids and only trace amounts of phospholipids and amino acids. Its inhibitory activity was not temperature dependent and it was almost completely neutralized by the addition of small amounts of normal rabbit serum. When serum was added to the inactive erythropoietin-lipid mixture, some, but not all, erythropoietin could be recovered. These results suggest that erythropoietin may be inactivated by a renal lipid during extraction procedures, thus accounting for the fact that renal extracts are erythropoietically inactive.