Tetrahydrogestrinone (often referred to as THG or
the "Clear") is a potent anabolic and progestagenic
androgenic steroid that is chemically and structurally
related to two other synthetic anabolic steroids,
gestrinone and trenbolone
(1). The "designer steroid" was derived by simple
chemical modification of another anabolic steroid
that is explicitly banned by the the World Anti-Doping
Agency (WADA).
Chemist
Patrick Arnold, the "father of prohormones"
in the U.S. sports nutrition market, is credited
with the creating THG via the catalytic hydrogenation
of gestrinone to evade detection. Patrick Arnold
along with Victor Conte of the Bay Area Laboratory
Co-operative (BALCO) were identified as the source
of THG which was distributed to several top athletics
in various sports in the American and European athletic
scenes. Unlike other anabolic-androgenic steroids
used illicitly by competitive athletes, which were
pharmaceuticals intended for veterinarian or human
use, THG had never been approved for any medical
indication nor introduced into commerce.
THG remained undetectable by sport doping control
urine tests for several years. This changed in the
summer of 2003 when Don Catlin director of the IOC/WADA
accredited laboratory in Los Angeles was mailed
a sample of a substance by an anonymous track coach
(later identified as Trevor Graham) that enabled
the structure of THG to be determined and a detection
methodology to be developed (2).
THG has since been prohibited both in and out
of competition under the World Anti-Doping Code.
The protocol for THG detection is used by IOC /
WADA accredited laboratories throughout the world
for sample analysis.
The use of tetrahydrogestrinone (THG) by several
elite athletes led the US Congress to add it to
the
Anabolic Steroid Control Act of 2004 as a "Schedule
III" controlled substance. THG, although pharmacologically
defined as an anabolic-androgenic steroid, was legally
defined as an "unapproved new drug" during its role
in the BALCO scandal.
References
Death AK, McGrath KC, Kazlauskas R, Handelsman
DJ. Tetrahydrogestrinone is a potent androgen
and progestin. J Clin Endocrinol Metab. 2004
May;89(5):2498-500
Catlin D. H., Sekera M. H., Ahrens B. D.,
Starcevic B., Chang Y. C., Hatton C. K. Tetrahydrogestrinone:
discovery, synthesis, and detection in urine.
Rapid Commun Mass Spectrom. 2004;18:1245–049.
Yu-Chen Chang; Borislav Starcevic; Brian
D. Ahrens; M. Jane Strouse; Don H. Catlin. Identification
of a Urinary Metabolite of the Designer Steroid
Tetrahydrogestrinone (THG). Drug Metab: Toxicology.
