Metabolic studies on erythropoietin (EP): II. The role of liver and kidney in the metabolism of Ep.

Half plasma disappearance time (HDT) of endogenous erythropoietin (Ep) was measured in single rats, using an in vitro assay system for EP. In rats treated with the hepatotoxic agent d-Galactosamine-HCl (GalN), a small but significant elevation of HDT was found as compared with control rats (164 and 105 min, respectively). In bilaterally nephrectomized rats mean HDT was significantly elevated: 266 min. Combination of nephrectomy and GalN treatment did not result in a significant further elongation of HDT (mean = 301 min). In experiments using isolated liver perfusion, rat livers (with and without GalN treatment) were shown to be unable to change perfusate Ep titre during 4 h of perfusion. It is concluded that hepatic degradation of Ep in rats is only minimal. The kidney however is important in the catabolism of Ep.