Zusammenfassung

Insulin, a potentially performance enhancing agent, is prohibited for non-diabetic athletes according to the WADA list of banned substances since 1999. Despite the already existing methods for the mass spectrometric determination of the chemically modified synthetic insulin analogues in regular doping control samples, an approach to uncover the misuse of recombinant human insulin is missing. Insulin is a peptide consisting of an A-chain (21 AA) and a B-chain (30 AA), which are connected by two disulfide bonds. It is endogenously produced in the pancreas from the single chain precursor proinsulin after cleavage into insulin and C-peptide (31 AA). In healthy individuals insulin and C-Peptide is secreted in equimolar amounts from the vesicles of the Langerhans` islets cells into the bloodstream. Thus, the ratio of these peptides in human plasma is supposed to be constant and a significant shift towards higher insulin amounts should provide a reliable hint for a surreptitious insulin application. Existing ELISA diagnosis kits for determination of insulin and C-peptide will be utilized to assess the physiological ranges of the ratio in regular plasma specimens and doping control samples. Moreover, specimens obtained from patients being treated with recombinant human insulin will be measured and serve as “positive control” samples. The planned methodology, which has commonly been used for clinical or forensic purposes, could also serve as a screening procedure for plasma doping control specimens to indicate the misuse of any kind of exogenous insulin supplement that cross-reacts with the employed ELISA.