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DOI: 10.1055/s-2007-991864
Measuring Orexin in body fluids: A new robust highly sensitive method
Orexin A is a small peptide-hormone that is essentially involved in the pathophysiology of narcolepsy and plays a crucial role physiologically in the regulation of eating behaviour. Thus, measuring Orexin A has been of great interest. However, physiological concentrations in blood and CSF are very low, in the range of 50–100 pg/ml serum. To our knowledge and in our vast experience there is not one commercial ELISA nor any commercially available antibodies to Orexin A that allow to reliably measure Orexin A in serum, plasma or CSF. There is one commercially available RIA that might be useful if customized. Apart from the analytical technology in ELISA/RIA the problem is that Orexin A is such a small peptide in low concentration in highly saturated protein-lipid fluids such as blood or CSF. Here, we present a new analytical technology that allows for robust high sensitive reliable analysis of Orexin A in body fluids. Using Q-MAP methodology by atto-lab GmbH (quantitative measurement of attomolar precipitation products) we established Orexin A analysis in blood and CSF. We can reliably detect physiological concentrations as well as the sub-physiological concentrations in narcolepsy. We will present our data on Orexin A analyses in healthy subjects as well as in narcoleptic subjects. We will be happy to collaborate for measuring Orexin A.