5α-Estrane-3ß,17ß-diol and 5ß-estrane-3α,17ß-diol: definitive screening biomarkers to sign nandrolone abuse in cattle?

17ß-Nandrolone (17ß-NT) is one of the most frequently misused anabolic steroids in meat producing animals. As a result of its extensive metabolism combined with the possibility of interferences with other endogenous compounds, detection of its illegal use often turns out to be a difficult issue. In recent years, proving the illegal administration of 17ß-NT became even more challenging since the presence of endogenous presence of 17ß-NT or some of its metabolite in different species was demonstrated. In bovines, 17α-NT can occur naturally in the urine of pregnant cows and recent findings reported that both forms can be detected in injured animals. Because efficient control must both take into account metabolic patterns and associated kinetics of elimination, the purpose of the present study was to investigate further some estranediols (5α-estrane-3ß,17ß-diol (abb), 5ß-estrane-3α,17ß-diol (bab), 5α-estrane-3ß,17α-diol (aba), 5α-estrane-3α,17ß-diol (aab) and 5ß-estrane-3α,17α-diol (baa)) as particular metabolites of 17ß-NT on a large number of injured (n=65) or pregnant (n=40) bovines. Whereas the metabolites abb, bab, aba and baa have previously been detected in urine up to several days after 17ß-NT administration, the present study showed that some of the isomers abb (5α-estrane-3ß,17ß-diol) and bab (5ß-estrane-3α,17ß-diol) could not be detected in injured or pregnant animals, even at very low levels. This result may open a new way for the screening of anabolic steroid administration considering these 2 estranediols as biomarkers to indicate nandrolone abuse in cattle.

Occurrence of alpha- and beta-nortestosterone residues in the urine of injured male cattle.

The administration of anabolic steroids, for the purposes of growth promotion, to food-producing animals is banned in the EU. Among the compounds covered by this prohibition is ss-nortestosterone (beta-NT). This hormone is known to occur naturally in stallions and boars, and its main bovine metabolite, alpha-nortestosterone (alpha-NT), occurs naturally in pregnant cows and neonatal calves. However, neither compound is believed to occur naturally in male cattle. During 2006, the presence of alpha-NT and, on occasion, beta-NT was confirmed in male cattle (bulls and steers) slaughtered in Northern Ireland on welfare grounds, as a result of acute injury. Subsequent investigations revealed no evidence of abuse at any of the farms involved and revealed that the phenomenon also occurred in three other regions of the EU, in similarly injured animals. A hypothetical link to release of the adrenal steroid, dehydroepiandrosterone (DHEA), in response to the stress of the injury was tested. Following the intravenous administration of DHEA to two normal steers, beta-NT (but not alpha-NT) was confirmed in the urine of one steer. Thus, it may be concluded that both beta-NT and, by implication, alpha-NT can occur naturally in male cattle (or a specific cohort thereof) in contrast to previously accepted scientific knowledge.