Erythropoietin in the urine of normal and erythropoietically abnormal human beings.

LTHOUGH THE CONCENTRATION of erythropoietin may rise to very high and easily measured levels under abnormal circumstances, the concentration in normal animals of many species, including man, is not sufficient to be consistently demonstrated in unconcentrated samples of serum or urine.’5 The fact that the administration to normal animals of antibodies against erythropoietin results in cessation of erythropoiesis#{176} is evidence that the hormone is essential for red cell production, and therefore must be present in low concentration in the body fluids of normal animals. Finne7 recently reported that concentrates of 24-hour collections of urine from normal male human beings produced an increase in Fe5#{176} incorporation in polycythemic mice equivalent to that obtained with approximately 0.4 standard B units of erythropoietin. It has been estimated indirectly that the concentration in plasma of normal human beings is in the order of 0.003 standard B units per ml.” To evaluate the relationship of erythropoietin to erythroid hypoplasia and mild degrees of hyperplasia, it would be advantageous to be able to measure the normal concentration. With presently available methods of assay, this requires concentrating the hormone from a large sample. As it may not always be possible to obtain large samples of plasma or serum, the urine was thought to provide the best starting material for detection of erythropoietin in normal human beings and patients with minimal acceleration or depression of erythropoiesis. This paper presents results using concentrates of human urine assayed for erythropoietin by the hypertransfused mouse Fe59 uptake assay.9