Comparison of three chemiluminescence detection methods for growth hormone secretagogues competitive receptor assay in urine

Abstract

The list of growth hormone secretagogue (GHS) products is growing steadily, which presents a challenge in sports drug testing. A method to alert on the abuse of emerging GHSs is relevant to support current target LC-MS methods. In this area, our research team presented a useful competitive radioreceptor assay method. However, as radioactive measurements are not implemented in all laboratories, an alternative competitive chemiluminescent receptor approach has been assessed with three different tags (alkaline phosphatase activity and horseradish peroxidase activity with their respective pre-luminescent substrates and acridinium). The method follows essentially the same sample preparation methodology of the initial radioactive approach, but exchanging the radioactive ghrelin ligand for ghrelin-biotin, which couples with streptavidin linked to the corresponding chemiluminescent tags. The usefulness of the approach is shown, although the sensitivity achieved is borderline for the detection of current administration studies.