A role of the kidney in the catabolism of erythropoietin in the rat

Plasma disappearance rate of exogenous and endogenous erythropoietin has been studied in the rat, in normal control animals, and after nephrectomy, ligation, or section of the ureters. Whereas in normal rats the T/2 with rat or sheep erythropoietin was, respectively, 1.5 and 1.9 hours, it was increased to 4.0 and 4.1 hours immediately after bilateral nephrectomy. The disappearance rate of endogenous erythropoietin after hypoxia was 3.8 hours in control animals against 8.3 hours in rats nephrectomized immediately after the arrest of the hypoxic stimulation. A normal disappearance rate of exogenous erythropoietin is found in uremic rats 20 hours after section of the ureters, slightly increased and similar T/2 are observed in rats investigated immediately or 48 hours after ureter ligation, whereas the disappearance rate in nephrectomized rats is significantly slower at 48 hours (T/2 = 12 hours) than immediately after bilateral nephrectomy. This discrepancy could signify that uremia per se has no effect on the catabolism of erythropoietin in the presence of renal parenchyma, but influences extrarenal catabolism of the hormone. These results suggest that the kidney, well-known to influence the metabolic fate of certain glycoproteins, also plays a role in the catabolism of erythropoietin. © 1974.SCOPUS: ar.j