WS2011 – LECTURE 75 K. Deventer 1 , S. Esposito 1 , D. De Boer 2 , O.J. Pozo 3 , G. Tsjoen 4 , F.T. Delbeke 1 , P. Van Eenoo 1 Is a simple detection approach possible for desmopressin? 1) Doping Control Laboratory (DoCoLab), Ghent University-UGent, Technologiepark 30, B-9052 Zwijnaarde, Belgium 2) Department of Clinical Chemistry, University Hospital Maastricht, Maastricht, The Netherlands 3) Institut Municipal d'Investigacio Medica (IMIM), Unitat de Farmacología, Barcelona, Spain 4) Department of Endocrinology–Andrology, Center for Sexology and Gender problems, Universitair Ziekenhuis Gent, De Pintelaan 185 9000 Gent Belgium Introduction Desmopressin is a small cyclicpeptide with a molecular weight of 1068 Da and is a synthetic analogue for arginine-vasopressin (AVP), the hormone that regulates urine production (Table 1). Due to the increased retention of water hemodilution can occur. This hemodilution can hamper the detection of blood doping which is generally monitored by blood- concentration dependent parameters like hematocrit and the absolute number and permillage of reticulocytes [1]. Table 1: vasopressin-analogues Compound Exact mass (Da) Structure Arginine-vasopressin (AVP) 1083 Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly-NH 2 Desmopressin 1068 Mpa-Tyr-Phe-Gln-Asn-Cys-Pro-D-Arg-Gly-NH 2 Terlipressin 1226 Gly-Gly-Gly-Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Lys-Gly-NH 2 Lypressin ([Lys8]-vasopressin) 1056 Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Lys-Gly-NH 2 [deamino-Cys1, Val4, D-Arg8]- Vasopressin 1039 Mpa-Tyr-Phe-Val-Asn-Cys-Pro-D-Arg-Gly-NH 2 Oxytocin 1006 Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH 2