Determination methods for erythropoietin receptor activator in human urine

In the present study, isoelectronic focusing with different pH gradients ( pH 3−5, 2−6) or migrating distances (8.5, 12 and 17 cm) and SDS-PAGE was used to separate continuous erythropoietin receptor activator (CERA), recombinant human erythropoietin (rhEPO), darbepoitin and endogenous EPO spiked in human urine with 37 ℃ overnight incubation.  Double blotting and chemiluminescent visualization were used to detect the IEF and SDS-PAGE profiles.  The bands of CERA profile were detected and well separated from the endogenous EPO and the other two EPO preparations with both SDS-PAGE and the IEF method using a gradient pH 3−5 and a migrating distance of 17 cm, and a significant particular band of CERA profile was found in the IEF result.  These preliminary results indicated that the methods were reliable and reproducible for detecting CERA, and could be used as a routine procedure for anti-doping analysis.