Plasma and renal clearance of exogenous erythropoietin in the dog

¹ Department of Biology, Graduate School of Arts and Science, New York University, and Department of Medicine, The New York Hospital-Cornell Medical Center, New York City

The pattern of plasma and renal clearance of purified sheep erythropoietin (ESF) was studied in unanesthetized dogs given a single intravenous injection of the hormone. Creatinine and PAH clearance measurements were also made up to 5 hr after ESF administration. Plasma clearance of ESF was found to be essentially biphasic: half-times for an initial rapid phase (0–1 hr) ranged from 20–45 min while those for the slower phase (1–24 hr) were of the order of 9–10.5 hr. Despite the loss from the plasma compartment of up to 70% of the injected dose of ESF within 3.5 hr, urinary recovery of the factor was quite low: about 2% of the injected dose in two experiments where 1,600 units were given and about 5% in a third experiment in which a dose of 3,200 units was employed. Excretion rates of the factor were found to be uniformly low and ESF clearance ranged from 0.1 to 0.6 ml/min. Some correlation between plasma levels and excretion rate of ESF was obtained. ESF clearance represented only a small fraction (0.1–1.4%) of the glomerular filtration rate. Injection of the hormone did not markedly influence creatinine or PAH clearance.

Key Words: erythropoietin metabolism in dogs • plasma and renal clearance of erythropoietin • plasma disappearance of exogenous erythropoietin • erythropoietin excretion rate

Submitted on February 28, 1964