Nortestosterone/trenbolone ELISA

• Material Safety Data Sheets
  

Intended Use

For the quantitative in vitro determination of 19-nortestosterone and trenbolone in serum, urine and tissue samples. This product is suitable for manual use only.


General Background

Growth-promoting hormones have been used by the livestock industry for over 30 years to improve an animal's ability to more efficiently utilize nutrients and produce leaner, more affordable meat. Concerns over the use of hormones in food producing animals first arose during the late 1970s and early 1980s, when a number of incidents linked hormone residues in meat with various medical conditions. As a result, the use of growth-promoting hormones in livestock production is either prohibited (European Union) or strongly regulated (e.g. USA, Canada and Australia). Compliance with these regulations is monitored by national monitoring programmes.

17β, 19-nortestosterone, commonly known as nandrolone, is an anabolic androgen that can be administered both intravenously and orally. It exists as a natural hormone in some animal species including pregnant cows and male pigs however is illegally used in animal husbandry as an anabolic steroid.

The European Union has provisionally prohibited the use of androgenic substances, such as 19-nortestosterone, in food producing animals; meaning that any detection of 19-nortestosterone, or its metabolites would be a violation. The European Union is currently working towards specifying minimum required performance limits (MRPLs) for assays for prohibited substances.

Trenbolone is an anabolic steroid with a structural similarity to testosterone. Trenbolone is normally administered as a trenbolone acetate ear implant, often in combination with other hormones. Trenbolone acetate is rapidly hydrolyzed in the circulation to produce 17a- and 17b-trenbolone. In bovine species 17-a trenbolone is the major metabolite detected in urine, faeces, bile and liver, whereas 17b-trenbolone is the major metabolite detected in muscle.

The regulatory approach to trenbolone residues is varied. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has recommended MRLs of 10ppb for 17-a trenbolone in liver and 2ppb for 17b-trenbolone in muscle, which have been adopted by Japan. However, the USA does not consider a tolerance for trenbolone to be necessary. The European Union has provisionally prohibited the use of androgenic substances, such as trenbolone, in food producing animals; meaning that any detection of trenbolone would be a violation.1 The European Union is currently working towards specifying minimum required performance limits (MRPLs) for assays for prohibited substances.


Principle

A micro titre plate is supplied precoated with a 19-nortestosterone antibody. 19-nortestosterone or trenbolone (antigen), if present in a sample competes with horseradish peroxidase labelled

19-nortestosterone (enzyme labelled antigen) for a limited number of antibody sites on the microtitre plate. The enzyme substrate is added.

After an incubation period to allow maximum colour development the colour reaction is stopped by the addition of Stop Solution, producing a colour change from blue to yellow. Absorbances are read at 450 nm.

The standard curve is then constructed in order to determine the equivalent 19-nortestosterone concentration in the serum, urine or tissue sample.