Methyltrienolone
Definition
Methyltrienolone (17β-hydroxy-17α-methylestra-3,9,11-trien-3-one, see Fig. 1 for structure) is a structural analogue of the anabolic androgenic steroid trenbolone (17β-hydroxyestra-3,9,11-trien-3-one, see Fig. 2 for structure), with a methyl group introduced at the C-17-alpha position.
Methyltrienolone is therefore also referred to synonymously as methyltrenbolone. Both compounds share the three double bonds between the C3-C4, C9-C10, and C11-C12 carbon atoms. Gestrinone and tetrahydrogestrinone (THG) also exhibit a similar basic structure. While trenbolone must be injected into the muscle in the form of a 17-acetate, methyltrienolone can be administered orally in tablet form.
While trenbolone has been approved for veterinary use (but not for human medicine), methyltrienolone has never been approved for medical use due to its high toxicity and severe side effects.
Since methyltrienolone binds very strongly to the androgen receptor, binds scarcely to plasma proteins, and is metabolized only minimally (1), the substance is frequently used in scientific studies as a reference compound (synonym: R1881) to characterize the binding properties of steroids to various receptors (e.g., the androgen receptor).
Significance as a Doping Agent
Both methyltrienolone and trenbolone are specifically listed as prohibited substances in sports under Group S1 (anabolic agents) on the World Anti-Doping Agency’s Prohibited List.
Both substances, particularly trenbolone, are promoted in bodybuilding as highly effective muscle-building hormones. The high binding affinity of methyltrienolone to the androgen receptor is cited as evidence of an extremely strong anabolic effect compared to other steroid hormones.
In elite sports, the first positive cases involving methyltrienolone were detected during doping tests in 2008. That year, a total of 15 Greek athletes (11 of whom were weightlifters) tested positive for the substance.
Side Effects
Both trenbolone and methyltrienolone were first synthesized in 1963. While the French company Roussel-Uclaf was able to market trenbolone for veterinary use, methyltrienolone was not further developed as a pharmaceutical due to its high toxicity. The increased side effects are also discussed extensively in bodybuilding forums on the internet.
See also Side Effects: Anabolic Androgenic Steroids
Detection
Methyltrienolone and trenbolone can be sensitively detected after isolation from urine samples using a combination of liquid chromatography and mass spectrometry.
References
- Guddat S, Schänzer W, Wachsmuth P, Thevis M: Doping control screening procedure for trenbolone analogues in human urine by LC-(APCI)-MS/MS. In: Schänzer W, Geyer H, Gotzmann A, Mareck U (eds.) Recent advances in doping analysis (15). Sportverlag Strauß, Cologne (2007) 397–400
- (1) Bonne C, Raynaud JP. Methyltrienolone, a specific ligand for cellular androgen receptors. Steroids 1975 Aug;26(2):227–32
