Studies on the erythropoietic stimulating factor in the plasma of mice after receiving testosterone.

Abstract

Abstract Plasma of mice injected with testosterone contained a detectable increase of an erythropoietic stimulating factor (ESF). ESF was no longer present if bilateral nephrectomy was performed 8 hours prior to collecting the plasma. On the other hand if both ureters were ligated 8 hours prior to sampling, the plasma levels were even higher than in unoperated mice. The plasma ESF activity following testosterone was neutralized by incubation with antierythopoietin, suggesting its identity with erythropoietin. We propose that testosterone stimulates erythropoiesis by altering the kidneys and thereby somehow increasing erythropoietin production.