title: Increased immunoreactive erythropoietin in serum and kidney extracts.
abstract: 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.
mesh_terms: D000818:Animals; D004921:Erythropoietin / Q000097:blood / Q000378:metabolism*; D006400:Hematocrit; D007668:Kidney / Q000378:metabolism*; D008297:Male; D009532:Nickel / Q000633:toxicity*; D011086:Polycythemia / Q000097:blood / Q000139:chemically induced / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors; D014020:Tissue Extracts / Q000032:analysis
chemical_list: D014020:Tissue Extracts; D004921:Erythropoietin; D009532:Nickel; C017557:nickel subsulfide