title: Endogenous nandrolone metabolites in human urine: preliminary results to discriminate between endogenous and exogenous origin.
abstract: When administered to human subjects, nandrolone is metabolized into two main products, 19-norandrosterone (19-NA) and 19-noretiocholanolone (19-NE). Recent studies demonstrated the endogenous production of these compounds in man at concentrations very close to the threshold of the International Olympic Committee (IOC), i.e. 2 ng/ml. Because the possibility of reaching or exceeding this fateful limit is difficult to exclude, a complementary biochemical parameter is necessary for the differentiation of endogenous 19-NA and 19-NE production from residues resulting from nandrolone consumption. We measured the endogenous concentrations of 19-NA and 19-NE in 385 urine samples from professional football players, and we studied the phase II metabolite composition in individuals excreting the highest concentrations. The results showed that around 30% of endogenous 19-norandrosterone was sulfo-conjugated, whereas 100% of 19-norandrosterone was excreted conjugated to a glucuronic acid when nandrolone was administered. This significant qualitative difference appears to be a promising complementary criterion to more definitively conclude about an athlete's culpability, especially when nandrolone metabolites are found in the low ng/ml range.
authors.affiliation: LABERCA, Ecole Nationale Vétérinaire, BP 50707, F-44087 Nantes Cedex 03, France. lebizec@ vet-nantes.fr
authors.forename: Bruno
authors.initials: B
authors.lastname: Le Bizec
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bryand
authors.forename: Isabelle
authors.initials: I
authors.lastname: Gaudin
authors.forename: Fabrice
authors.initials: F
authors.lastname: Monteau
authors.forename: Frédéric
authors.initials: F
authors.lastname: Poulain
authors.forename: François
authors.initials: F
authors.lastname: Andre
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid; D004032:Diet; D004962:Estranes / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D020719:Glucuronides / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009277:Nandrolone / Q000008:administration & dosage / Q000378:metabolism* / Q000652:urine*; D015813:Substance Abuse Detection / Q000379:methods*; D013431:Sulfates / Q000378:metabolism
chemical_list: D004962:Estranes; D020719:Glucuronides; D013431:Sulfates; C036015:19-norandrosterone; D009277:Nandrolone