数据之源，洞见之始

Metabolite Card

Note

19-Nor-5-androstenediol is an androgen steroid that has been found to be part of nutritional supplements that are commercialized as nandrolone-free. Some reports regarding nandrolone-positive cases have been related to intake of some of these supplements. Nandrolone is the most frequently abused substance in doping control because it does not convert to estrogens and does not have and androgenic side effects. For this reason, one the major metabolites of nandrolone, 19-norandrosterone (19-NA) have been used as determinants for doping of nandrolone. However, there are situations where the occurrence of nandrolone metabolites is a phenomenon not necessarily associated with doping: a) in human ovarian follicular fluid is a possible intermediate in the multistep enzymatic conversion of androgen to estrogen, b) during the course of pregnancy, 19-NA increases in urine, c) human chorionic gonadotropin (hCG) also stimulates 19-NA excretion in urine, d) exercise has been shown to affect the urinary excretion of nandrolone metabolites such as 19-NA, e) 19-NA is a minor metabolite of oral contraceptives such as norethisterone. Furthermore, 19-NA is the main urinary metabolite of 19-Nor-5-androstenediol. Nevertheless, the prevalence of nandrolone abuse is evident; internationally, 212 cases were found in 1995 and 232 cases were found in 1996. From 1998 to 2001, nandrolone-positive findings reported by the IOC-accredited laboratories ranged from 0.17% to 0.65%. (PMID: 15902981).