Detectability of testosterone esters and estradiol benzoate in bovine hair and plasma following pour-on treatment

Abstract

The abuse of synthetic esters of natural steroids such as testosterone and estradiol in cattle fattening and sports is hard to detect via routine urine testing. The esters are rapidly hydrolysed in vivo into substances which are also endogenously present in urine. An interesting alternative can be provided by the analysis of the administered synthetic steroids themselves, i.e., the analysis of intact steroid esters in hair by liquid chromatography tandem mass spectrometry (LC/MS/MS). However, retrospective estimation of the application date following a non-compliant finding is hindered by the complexity of the kinetics of the incorporation of steroid esters in hair. In this study, the incorporation of intact steroid esters in hair following pour-on treatment has been studied and critically compared with results from intramuscular treatment. To this end animals were pour-on treated with a hormone cocktail containing testosterone cypionate, testosterone decanoate and estradiol benzoate in different carriers. The animals were either treated using injection and pour-on application once or three times having 1 week between treatments using injection and pour-on application. Animals were slaughtered from 10–12 weeks after the last treatment. Both hair and blood plasma samples were collected and analysed by LC/MS/MS. From the results, it is concluded that after single treatment the levels of steroid esters in hair drop to CCβ levels (5–20 µg/kg) after 5–7 weeks. When treatment is repeated two times, the CCβ levels are reached after 9–11 weeks. Furthermore, in plasma, no steroid esters were detected; not even at the low microgramme per litre level but—in contrast with the pour-on application—after i.m. injection, significant increase of 17β-testosterone and 17β-estradiol were observed. These observations suggest that transport of steroid esters after pour-on application is not only performed by blood but also by alternative fluids in the animal so probably the steroid esters are already hydrolysed and epimerized before entering the blood.

A review of analytical strategies for the detection of ‘endogenous’ steroid abuse in food production

“…Steroid esters (hair, plasma/serum, muscle) [49][50][51][52][53][54][55][56][57][58] -Can be used for both screening and confirmation.…”

“…The detection of intact steroid esters in hair has attracted the most attention in literature for this purpose and has already found use in some European labs as a confirmatory technique for proving natural steroid abuse. [49][50][51][52][53][54][55] When dealing with hair, however, contamination issues need to be carefully considered in order to eliminate environmental contamination as a possible cause of false non-compliant results.…”

Natural Hormones in Food-Producing Animals:Legal Measurements and Analytical Implications

“…Although the administration of esters of natural hormones can be detected through hair analysis (Duffy et al, 2008;Grataco s-Cubarsi et al, 2006;Pedreira et al, 2007;Rambaud et al, 2005), it has been very difficult to detect intact steroid esters in body fluids or tissues. It is likely that esters quickly hydrolyze in the body of the animal, releasing the corresponding natural hormone (Stolker et al, 2009). So, the www.intechopen.com simple detection and confirmation of the presence of these semisynthetic versions are not always possible.…”

“…So, the www.intechopen.com simple detection and confirmation of the presence of these semisynthetic versions are not always possible. That is particularly true for estradiol benzoate, which has only been detected in hair up to date (Duffy et al, 2009;Hooijerink et al, 2005;Rambaud et al, 2005;Stolker et al, 2009), because estradiol benzoate undergoes the loss of the ester group once it reaches the bloodstream. In order to detect the administration of these esterified substances, new analytical approaches are required, in the same manner that they are required to detect the administration of exogenous hormones in their natural chemical form (estradiol, testosterone or progesterone).…”

Immunosensing with artificial antibodies in organic solvents or complex matrices

“…In this article we extended the method to different analytes as well as more relevant matrices as plasma or food samples. We employ the principle of polymeric antibody copies to detect the following bioanalytes: sesame protein, which has been recognized as an increasingly frequent and potentially serious allergen [30] and estradiol and its structural analogues, which are serious pollutants due to their influence on the hormonal system [31]. Furthermore, we present a new way to pre-concentrate and measure hormons in an organic solvent.…”