Possible Doping in Sports - Term Paper Example

Possible Doping in Sports The misuse of drugs in human sports in an attempt to enhance performance, usually known as doping, is unfortunately an extensive and old practice. Ethical and health aspects are of particular concern. Sports, fair play, medical ethics and potential risks for the health of the athlete leads to consider this practice unacceptable. The definition of doping adopted in the World Anti-doping Code is the occurrence of one or more of a set of doping rules violations. Among them, reference is made to: the presence of a prohibited substance in an athlete’s body specimen, the use of a prohibited substance or method, refusing or evading sample collection, tampering, trafficking or even assisting or any other type of complicity with a doping violation. The medical commission of the IOC has created a list of forbidden substances and prohibited methods, which is included in the IOC’s medical code. Doping control is performed by a network of IOC accredited laboratories, which analyze urine samples collected after or out of competition. The Prohibited List (List) was first published in 1963 under the leadership of the International Olympic Committee. Since 2004, it had been updated and published by the WADA. The List is the cornerstone of the Code and a key component of harmonization. It lists substances and methods prohibited in and out of competition, as well as substances prohibited for particular disciplines. The use of prohibited substances can be authorized for medical reasons by virtue of a TUES. The substances that top this list are Anabolic Agents indicated by Anabolic Androgenic Steroids (AAS), e.g., testosterone, nandrolone, methandienone, and stanozolol. Substances prohibited in all situations are anabolic agents mainly steroids, hormones, beta 2-agonists, agents with anti-estrogenic activity, diuretics and masking agents. All these banned substances must not be present in tested urine samples, therefore, laboratories report the presence of such compounds in the samples on a qualitative basis. Urine samples are routinely used to perform doping control in athletes. Urine is the preferred fluid because its collection is non-invasive. It is generally available in sufficient quantity, and the drugs and/or their metabolites are in general present in relatively high concentrations. The main disadvantage of urine is that the drug can be excreted either as free or conjugated metabolites, and the parent drug may be present in relatively low concentrations (IOC Medical Commission). The purpose of the International Standards for Testing is to plan for effective testing and to maintain the integrity and identity of samples throughout the testing process, from notifying the athlete to transport of the samples for analysis. The purpose of the International Standard for Laboratories (ISL) is to ensure production of valid test results and evidentiary data, and to achieve uniform and harmonized results and reporting from all accredited laboratories. When looking at the statistics of 2004, anabolic steroids are still the most often reported doping agents, as it has been the case every year since the beginning of the 1990s. The large number of testosterone cases should be taken with caution because the differentiation between a naturally elevated concentration of the endogenous hormone and abuse of testosterone esters cannot always be done (Mottram and George, 2000, 55-69). Anabolic steroids are synthetic derivatives of testosterone modified to enhance the anabolic rather than the androgenic actions of the hormone. Testosterone is hormone-synthesized in the human body from cholesterol. It serves distinct functions at different stages of life. During embryonic life, androgen action is central to the development of the male phenotype. At puberty, the hormone is responsible for the secondary sexual characteristics that transform boys into men. Testosterone intervenes in many physiological processes in the adult male including muscle protein metabolism, sexual and cognitive functions, erythropoiesis, plasma lipids, and bone metabolism. Synthetic anabolic steroids belong to the pharmacological group with major impact on drug abuse in sport. All compounds belonging to this class resemble testosterone in their chemical structure but with a series of modifications that have major impact on the way metabolic enzymes of the human and animal body modify their structures during biotransformation process. Testosterone is virtually inactive when taken orally. After oral ingestion, testosterone is absorbed from the small intestine and passes via the portal vein to the liver where it is rapidly metabolized, mostly to inactive compounds. Accordingly, chemical modifications of testosterone have been made to alter the relative anabolic–androgenic potency, slow the rate of inactivation, and change the pattern of metabolism. Most orally anabolic-androgenic steroids (AAS) preparations are 17-beta alkylated derivatives of testosterone that are relatively resistant to hepatic inactivation. Esterification of the 17-beta hydroxyl group makes the molecule more soluble in lipid vesicles for injection. This slows the release of the injected steroid into the circulation. Evidence suggests that with normal male physiological plasma levels of testosterone, the androgen receptors, to which testosterone and dihydrotestosterone bind, are fully saturated. In vitro studies have demonstrated that the dose–response relationship of testosterone and skeletal muscle growth reaches a plateau once the physiological concentration is exceeded (Baume et al. 2005, 158-164). It has been suggested that when anabolic steroids are abused by athletes, the drugs exert their effects by another receptor mechanism that is unsaturated or unaffected by normal plasma testosterone and DHT levels. Indeed, it is believed that the effects of supraphysiological doses of testosterone on muscle are mediated through an antiglucocorticoid action, independent of the androgen receptor (Bricout and Wright, 2004, 1-12). In recent years, the administration of metabolic precursors of testosterone is increasing among athletes who try to improve their performance with anabolic androgenic steroids and to escape from easy detection. Findings in urine of abnormal concentrations of these compounds, which are always normally present in the human body, are indicative of a prohibited use. AAS are generally accepted as having the desired anabolic effects, provided athletes also have an adequate protein supply and exercise intensely. In a randomized controlled trial, those taking 600 mg testosterone intramuscular injections weekly for 10 weeks had significantly increased muscle mass, muscle strength, and fat-free mass compared to those taking a placebo. However, not all studies have found such strength gains (Evans, 2004, 534-542). Testing for anabolic agents in the urine of athletes was first implemented on a large scale during the 1976 Montreal Olympic Games. Testing was mainly based on radioimmunoassay (RIA) techniques. The techniques for the identification and characterization of steroids and their metabolites in urine have improved considerably during the last three decades. This improvement is largely due to the use of gas chromatography-mass spectrometry (GC-MS) techniques. Today, most antidoping laboratories use techniques that are based on the solid-phase extraction of the urine sample, followed by chemical modifications prior to GC-MS analysis. The confirmation procedure for the unequivocal identification of an anabolic doping agent consists in matching GC and MS data of the supposed substance and/or its metabolites with pure standards, or matching the metabolite profile of the sample with reference urine originating from an excretion study. The detection of exogenous substances requires the identification of a parent compound and/or at least one metabolite. However, with endogenously produced substances, such as, testosterone, the presence of the substance alone cannot be considered as an offense. Moreover, a cutoff value for testosterone concentration cannot be used because of large inter-individual and intra-individual urinary concentrations of the hormone. However, the intake of testosterone causes characteristic changes in the pattern of steroids excreted in the urine. In 1983, based on studies performed on athletes, the IOC adopted a ratio of testosterone to epitestosterone (T/E) of up to 6.0, as a criterion for the administration of testosterone. Epitestosterone formation seems to parallel testosterone formation, but it does not increase to the same extent as testosterone after exogenous testosterone administration, resulting in an increase of the T/E ratio (Saudan et al., 2006, i21-i24). In populations of athletes, a mean T/E ratio of less than 2.0 is observed. For that reason the IOC rules clearly state that a T/E ratio greater than 6.0 constitutes an offense, unless there is evidence that the result is due to an extraordinary physiological or pathological condition such as, low epitestosterone excretion, androgen producing tumor, and enzyme deficiencies. Before a sample is declared positive, further investigations are conducted as a confirmational study. As a first step, a comparison with previous values is made. After that, or if no previous values are available, several additional urine samples are analyzed over a short period. This longitudinal study may represent a useful tool to detect false-positive results, naturally elevated T/E ratios (Saugy et al., 2000, 111-133). In this given scenario, the player has tested positive for anabolic steroids in the range of a T:E ration of 11:1. Before sending the report, the medical officer must think about the fact that the player might have been medically treated with such medications. A number of clinical studies using a variety of experimental designs have shown that the potent anabolic effects of AAS have a positive effect on various pathological conditions. Physiologic replacement doses of testosterone have been used to stimulate sexual development in cases of delayed puberty, and to substitute for the hormone after surgical removal of a testis. The first major clinical use of anabolic steroids was to inhibit the loss of protein and aid muscle regeneration after major surgery. Anabolic steroids may also be used to increase growth in prepubertal boys who have failed to reach their expected minimal height for their age. Since none of these conditions seemed to have existed in this female volleyball player, it is highly likely that despite playing innocence, she has doped using anabolic steroids (IOC List of Classes, 1999). WADA suggested in 2004 that urine samples should now be submitted to isotopic ratio mass spectrometry (IRMS) if the T/E is greater than or equal to 4.0, and testosterone, testosterone metabolites, epitestosterone, and DHEA concentrations are greater than fixed cutoff concentrations. Even if additional studies of the particular athlete suggest the potential steroid profile manipulation, there is a lack of definitive proof for the exogenous application of natural steroids. This problem can be solved by the determination of the ratio of the two stable carbon isotopes 13C/12C, which allow the differentiation of natural and synthetic steroids. As exogenous testosterone or precursors contain less 13C than their endogenous homologues, a lower urinary 13C/12C ratio can be expected if steroids have been administered (Aguilera et al., 2002, 629). The latest list of prohibited substances, established by the WADA for 2005, includes two types of steroids: (1) typically exogenous steroids, main examples of which have been given previously, and (2) typically endogenous steroids, e.g., androstenediol, androstendione, dehydroepiandrosterone (DHEA), dihydrotestosterone (DHT), testosterone, and related substances. In fact, only small amounts of unchanged anabolic steroids are excreted unchanged in urine. The metabolism involves very often the introduction of hydroxyl groups which are further conjugated by glucuronidation and, to a lesser extent, sulphation (Verroken, 2000, 1-23). Thus, hydrolysis of those conjugates is a fundamental step in many of the analytical methods used. When metabolites of anabolic steroids are free from their conjugates, or in those few cases where non-conjugated metabolites are directly excreted in urine, a simple extraction from the matrix interferences is needed. Liquid-liquid extraction is often used after adjusting pH to values of around 9-10. Different solvents have been used, but diethyl ether or tert-butylmethyl ether are the preferred ones. The method for determining the isotopic composition of the relevant analyte includes GS, a subsequent combustion to CO2, and, finally, MS analysis of the gas in a special multicollector mass spectrometer (isotope-ratio-mass-spectrometry, IRMS). The 13C/12C ratio of testosterone or its metabolites is measured and compared to urinary reference steroids within the sample. It should be emphasized that the 13C/12C ratio of these endogenous reference compounds should not be affected by steroid administration. The result will be reported as consistent with the administration of a steroid, if a significant difference is observed between the 13C/12C values of testosterone metabolites and the endogenous reference compound. According to population studies, the WADA Laboratory Committee has stated a difference cutoff for positivity in 2004. If the IRMS study does not clearly indicate exogenous administration, an inconclusive result may be reported and further longitudinal studies can be performed (Dehennin, 1994, 106-109). Literature explains the importance of T:E ratio in the context of its physiological implications. Epitestosterone is the 17α epimer of testosterone that is a naturally occurring steroid found in urine in concentrations similar to those of testosterone. This does not have any physiological role. This is of great interest in doping control because it is the denominator in the T:E ratio, an indirect marker of testosterone administration. When testosterone is exogenously administered, the excretion rate of urinary testosterone increases with a concomitant decline in epitestosterone. An increased T:E ratio also indicates indirectly the presence of androstenedione and dehydroepiandrosterone. Quite logically, as mentioned earlier, of the T:E ratio exceeds 6, the doping control laboratories report the case to the sports authorities and recommend investigations of the cause of the increase T:E ratio. This case also demands investigation. To this end, the latest development is the measurement of δ13C values of urinary epitestosterone by IRMS method (Carlstrom et al., 1992, 1779-1784). Although exogenous testosterone causes marked and characteristic changes in the pattern of steroids excreted in the urine and the formation of epitestosterone in inhibited by exogenous testosterone. By all sports authorities, it is agreed upon that above normal T:E ratio in the urine is a reliable indicator of testosterone doping. Results from antidoping laboratories indicate that genetic, environmental, and dietary factors may affect this ratio leading to false positive results. The implications are serious. This indicates, additional criteria for testosterone doping detections are needed. Decreased urinary luteinizing hormone excretion or increased urinary T/LH ratio has been suggested to be another alternative for detection of anabolic steroid doping (Starka, 2003, 27-34). Another strategy could be to measure the T:E ratio in urine samples collected at various intervals after the collection of the first sample with an increased ratio. The basis of this concept is that if testosterone has been administered, the T:E ratio is expected to change over time. Exogenously administered testosterone is converted to estrogen to some extent. An idea has been advanced in this context that urinary estrogen can be a marker of testosterone doping. Supplementary analysis of a serum sample can provide additional supportive and useful information. These methods can be useful to diagnose doping in the volleyball player, and before advancing recommendations, it is very important for the medical officer to take a cautious decision. For antidoping work, it is important that the analytic procedure be as maximally accurate as possible. It is also important for the analytic process to eliminate all possible risks for false positive results. In all suspected cases of testosterone doping, some researchers have come up with suggestions of supplementary immunological analysis of 17OH progesterone, Testosterone, and LH. To this end, a highly sensitive immunoassay of 17OHP, preferably including an extraction step to improve specificity could be used. Moreover, in such cases, there is always probability of legal consequences, the best way would be have backup testosterone quantification and quantification of 17OH progesterone by isotope dilution mass spectroscopy (Carlstrom et al., 1992, 1779-1784). Reference List Aguilera, R., Hatton, CK., and Catlin, DH., (2002). Detection of Epitestosterone Doping by Isotope Ratio Mass Spectrometry. Clin. Chem.; 48: 629. Baume N, Avois L, Sottas PE, et al. (2005). Effects of high-intensity exercises on 13C-nandrolone excretion in trained athletes. Clin J Sport Med;15(3):158–66. Bricout V, Wright F. (2004). Update on nandrolone and norsteroids: how endogenous or xenobiotic are these substances? Eur J Appl Physiol;92(1–2):1–12. Carlstrom, K., Palonek, E., Garle, M., Oftebro, H., Stanghelle, J., and Bjorkhem, I., (1992). Detection of testosterone administration by increased ratio between serum concentrations of testosterone and 17 alpha-hydroxyprogesterone. Clin. Chem.; 38: 1779 - 1784. Dehennin, L., (1994). Detection of simultaneous self-administration of testosterone and epitestosterone in healthy men. Clin. Chem.; 40: 106 - 109. Evans NA. (2004). Current concepts in anabolic-androgenic steroids. Am J Sports Med;32(2):534–42. IOC Medical Commission, IOC List of Classes of Prohibited Substances and Methods of Doping, Medical Code and Explanatory Document, Laussanne International Olympic Committee, 1995(updated 3 1 st January 1999). Mottram DR, George AJ., (2000). Anabolic steroids. Baillieres Best Pract Res Clin Endocrinol Metab; 14(1):55–69. Saudan, C., Baume, N., Robinson, N., Avois, L., Mangin, P., and Saugy, M., (2006). Testosterone and doping control. Br. J. Sports Med.; 40: i21 - i24. Saugy M, Cardis C, Robinson N, Schweizer C., (2000). Test methods: anabolics. Baillieres Best Pract Res Clin Endocrinol Metab;14(1):111–33. Starka L. (2003). Epitestosterone. J Steroid Biochem Mol Biol;87(1):27–34. Verroken M., (2000). Drug use and abuse in sport. Baillieres Best Pract Res Clin Endocrinol Metab;1 4(1):1–23. Read More