Metabolic studies of mesterolone in horses

Anal Chim Acta. 2007 Jul 16;596(1):149-55. Epub 2007 Jun 3
Ho EN, Leung DK, Leung GN, Wan TS, Wong HN, Xu X, Yeung JH.
Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, NT, Hong Kong, China
PubMed ID & Record: 17616252

Mesterolone (1alpha-methyl-5alpha-androstan-17beta-ol-3-one) is a synthetic anabolic androgenic steroid (AAS) with reported abuses in human sports. As for other AAS, mesterolone is also a potential doping agent in equine sports. Metabolic studies on mesterolone have been reported for humans, whereas little is known about its metabolic fate in horses. This paper describes the studies of both the in vitro and in vivo metabolism of mesterolone in racehorses with an objective to identify the most appropriate target metabolites for detecting mesterolone administration. In vitro biotransformation studies of mesterolone were performed by incubating the steroid with horse liver microsomes. Metabolites in the incubation mixture were isolated by liquid-liquid extraction and analysed by gas chromatography-mass spectrometry (GC-MS) after acylation or silylation. Five metabolites (M1-M5) were detected. They were 1alpha-methyl-5alpha-androstan-3alpha-ol-17-one (M1), 1alpha-methyl-5alpha-androstan-3beta-ol-17-one (M2), 1alpha-methyl-5alpha-androstane-3alpha,17beta-diol (M3), 1alpha-methyl-5alpha-androstane-3beta,17beta-diol (M4), and 1alpha-methyl-5alpha-androstane-3,17-dione (M5). Of these in vitro metabolites, M1, M3, M4 and M5 were confirmed using authentic reference standards. M2 was tentatively identified by mass spectral comparison to M1. For the in vivo metabolic studies, Proviron (20 tablets x 25 mg of mesterolone) was administered orally to two thoroughbred geldings. Pre- and post-administration urine samples were collected for analysis. Free and conjugated metabolites were isolated using solid-phase extraction and analysed by GC-MS as described for the in vitro studies. The results revealed that mesterolone was extensively metabolised and the parent drug was not detected in urine. Three metabolites detected in the in vitro studies, namely M1, M2 and M4, were also detected in post-administration urine samples. In addition, two stereoisomers each of 1alpha-methyl-5alpha-androstane-3,17alpha-diol (M6 and M7) and 1alpha-methyl-5alpha-androstane-3,16-diol-17-one (M8 and M9), and an 18-hydroxylated metabolite 1alpha-methyl-5alpha-androstane-3,18-diol-17-one (M10) were also detected. The metabolic pathway for mesterolone is postulated. These studies have shown that metabolites M8, M9 and M10 could be used as potential screening targets for controlling the misuse of mesterolone in horses.

Liposynovitis prepatellaris in athletic runner (Hoffa's syndrome): case report and review of the literature.

Clin Rheumatol. 2007 Jul;26(7):1201-3. Epub 2006 May 31.
Emad Y, Ragab Y.
Rheumatology & Rehabilitation Department, Faculty of Medicine, Cairo University, Cairo, Egypt.
PubMed ID & Record: 16736123

A 37-year-old male patient, who is an athletic runner, developed anterior knee pain of acute onset after prolonged running and swelling of his right knee. The patient experiences more pain when he flexes the knee and a sense of catching together with grade 1 effusion. The patient was clinically suspected to have internal derangement and MRI study of his right knee was ordered to exclude such possible diagnosis. The MRI study revealed the following: a hypointense lesion in the infrapatellar pad of fat in T2-weighted images (WI), postcontrast T1 WI with fat saturation demonstrated no enhancement, and STIR sequence showed slightly hyperintense lesion with minimal knee effusion. The MRI findings supported the diagnosis of Hoffa's syndrome, and arthroscopic resection of the fat pad was performed. There was a significant improvement in the symptoms and function after the surgery.

Induction of micronuclei in V79 cells by the anabolic doping steroids

Dorn SB, Bolt HM, Thevis M, Diel P, Degen GH.
Leibniz Research Centre for Working Environment and Human Factors, Institut fur Arbeitsphysiologie an der Universitat Dortmund (IfADo), Ardeystr. 67, 44139, Dortmund, Germany
PubMed ID & Record: 17764006

The synthetic steroid tetrahydrogestrinone is a new "designer drug" and was recently detected to be illegally used in sports. It is chemically closely related to trenbolone that is known as an animal growth promoter. The potencies of trenbolone, tetrahydrogestrinone and testosterone to induce micronuclei in V79 cells in vitro were determined. CREST analysis was employed to differentiate between aneugenic or clastogenic mechanisms. Cytotoxicity and an influence on the cell cycle were assessed in parallel. Incubations with testosterone, at concentrations between 3 and 300 muM, failed to induce micronuclei. By contrast, tetrahydrogestrinone and trenbolone increased the rate of micronuclei significantly, up to a doubling of the micronuclei rate of untreated controls. Tetrahydrogestrinone and trenbolone displayed a bell-shaped dose-response curve, with maximal effects observed at 3 and 30 muM, respectively. The micronuclei induced by tetrahydrogestrinone and trenbolone were predominantly kinetochor (CREST) positive, pointing to an aneugenic mode of action. This may be related to the specific structure of both molecules with a system of activated double bonds. As the genotoxic effect of tetrahydrogestrinone at a chromosomal level appears at a low concentration range, it cannot be ruled out that tetrahydrogestrinone presents a genotoxic hazard on a chromosomal level under conditions of its current misuse in sports.

Beta2-agonist clenbuterol induced changes in the distribution of white blood cells in rats

J Pharmacol Sci. 2007 Jun;104(2):146-52. Epub 2007 Jun 8
Shirato K, Tanihata J, Motohashi N, Tachiyashiki K, Tomoda A, Imaizumi K.
Laboratory of Physiological Sciences, Faculty of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa 359-1192, Japan.
PubMed ID & Record: 17558185

Clenbuterol [CLE: 4-amino-alpha(t-butyl-amino)methyl-3,5-dichlorobenzyl alcohol] is well known as a potent beta2-adrenergic agonist and non-steroidal anabolic drug, and thus it is generally used for sports doping and asthma therapy. Although the functions of immune cells such as white blood cells (WBCs) have shown to be modulated through beta2-adrenoceptors, the effects of CLE on immune-responsive systems have not been elucidated systematically. Therefore, the effects of CLE on the number of WBCs were studied in rats. Male adult rats were divided into CLE-administered group and the control group to compare the number of total WBCs, neutrophils, monocytes, lymphocytes, eosinophils, and basophils. The administration (dose = 1.0 mg . kg(-1) body weight . day(-1), s.c.) of CLE was maintained for 30 days. CLE did not change the number of total WBCs during the experimental period. However, CLE increased significantly the number of neutrophils and monocytes, while CLE decreased drastically the number of lymphocytes and eosinophils. There was no significant change in the number of basophils between both groups. These results suggest that the administration of CLE induces drastic redistribution of WBCs in circulation without changing the number of total WBCs, and these responses of WBCs during the administration of CLE are sustained for at least 30 days.