Effects of erythropoietin administration in training athletes and possibleindirect detection in doping control

Purpose: This study investigated the effects of repeated subcutaneous injec tion of rRuEpo (50 IU.kg(-1)) in athletics and proposes a method based on t he measurement in blood samples of the sTfR/serum protein ratio to determin e if the observed values of this marker are related to rHuEpo abuse. Method s: Serum erythropoietin concentrations, and hematological and biochemical p arameters were evaluated, during treatment and for 25 d posttreatment in ni ne training athletes, Moreover, the effect of rHuEpo administrations on the maximum oxygen uptake ((V) over dot O-2max) and ventilatory threshold (VT) of these athletes was also studied. Threshold values for sTfr and the sTfr /serum protein ratio were determined from 233 subjects (185 athletes, 15 at hletes training at moderately high altitude, and 33 subjects living at >300 0 m). Results: Significant changes in reticulocytes, hemoglobin (Hb) concen tration, hematocrit (Hct), sTfr, and sTfr/serum proteins were observed duri ng and after rHuEpo treatment. The maximal heart rate of 177 beats.min(-1) at the beginning of the study was significantly higher than the value of 16 8 beats.min(-1) after 16 d of rHuEpo administration. Compared with the valu es measured at baseline, the VT measured after rHuEpo administration occurr ed at a statistically significant high level of oxygen uptake. Conclusions: When oxygen uptake measured at the VT was expressed as a percentage of (V) over dot O-2 max, the values obtained were also significantly higher. The increased values of Tfr and sTfr/serum proteins, respectively, above 10 mu g.mL(-1) and 153, indicated the probable intake of rHuEpo.