Hopfer S M, Sunderman F W, Reid M C, Goldwasser E
Res Commun Chem Pathol Pharmacol. 1984 Feb;43(2):299-305.
Radioimmunoassay of erythropoietin (epo) was performed upon serum samples and kidney extracts from rats that received intrarenal injections of nickel subsulfide (Ni3S2, 20 mg/rat). Serum epo concentrations were significantly increased from 1 to 4 weeks after Ni3S2 injection; the highest values occurred at 3 weeks, when serum epo in 5 Ni3S2-treated rats averaged 230 mU/ml (range = 94 - 370 mU/ml); for comparison, serum epo in 21 vehicle-treated controls averaged 19 mU/ml (range = less than 14 - 56 mU/ml, P less than 0.01). In kidney extracts of 5 rats killed 3 weeks after Ni3S2 injection, epo concentrations averaged 970 mU/g (range = 210 - 1880 mU/g); for comparison, epo in kidney extracts of 6 controls averaged 99 mU/g (range = 40 - 140 mU/g, P less than 0.005). These radioimmunoassays confirm previous bioassays findings that serum epo concentrations are significantly increased in rats with Ni3S2-induced erythrocytosis. Contrary to bioassay findings, this study demonstrates increased immunoreactive epo concentrations in kidney extracts of Ni3S2-treated rats, suggesting that renal epo in Ni3S2-treated rats occurs in a form that lacks biological activity in vivo.
