Doping: a Cocktail of Chemicals

The prestigious cyclist Lance Armstrong was stripped of his seven Tour de France titles and his dignity in 2012, after finally confessing to using performance-enhancing drugs. Now, Armstrong has said that if asked to repeat his decision, he would commit the same offences due to the pervasive nature of doping in competitive cycling at the time. But what drugs did the cyclist and his peers use, and what chemicals are responsible for their superhuman qualities?

(Reuters/Stefano Rellandini)

(Reuters/Stefano Rellandini)

A major aspect of performance enhancement at the time was blood doping. This involved boosting the level of blood cells in the blood, a natural process involving erythropoietin (EPO). This glycoprotein is made in the kidneys in response to low blood oxygen levels, and targets the bone marrow where it stimulates the production of red blood cells. Recombinant human EPO (rHuEPO) is used medically for patients suffering from anaemia as a result of kidney dysfunction, cancer, or AIDS treatment. However, in healthy subjects it maximises arterial O2 by increasing red blood cell production and decreasing plasma volume; multiple studies have shown that rHuEPO boosts athletic performance. Armstrong and many others abused this chemical, injecting it into their bloodstream to increase their oxygen-carrying capacity. When the test for EPO became more sophisticated, athletes had transfusions of their own blood to imitate its effect.

Red Blood Cell (photo credit Rice University)

Red Blood Cell (photo credit Rice University)

Cyclists also used androgenic anabolic steroids, banned since 1974, to increase their bodyweight and strength by modulating androgen receptor expression, and inducing an anti-catabolic effect. Fellow athlete Tyler Hamilton reported seeing Armstrong consuming Andriol, an oral steroid compound containing testosterone undecanoate, a modified form of testosterone with an 11 carbon chain ester. This ester is so lipophilic that it can be absorbed through the lymphatic system to avoid the liver damage that is usually incurred by ingesting testosterone. Long-term use of anabolic steroids causes increased lean body mass, muscle fibre area and size, and capillary and myonuclei density which causes a massive advantage in muscular performance compared to ‘clean’ individuals. Other long-term effects are extensive and less attractive, including gynaecomastia or ‘man boobs’, psychiatric disturbance and severe effects on several organ systems.

Gynaecomastia

Gynaecomastia

Another steroid banned by the WADA is cortisone, which Armstrong actually tested positive for in 1999 – however, the use of glucocorticoids is permitted with a medical exemption, and he was not charged with doping after the production of an old prescription of cortisone for saddle sores. Glucocorticoids stimulate gluconeogenesis and mobilization of fatty acids and amino acids, preventing fatigue and inflammation so that athletes can sustain pain that would otherwise be excruciating.

The illegal use of human growth hormone was also rife within the cycling team. Somatotropin is polypeptide hormone synthesised and secreted by the anterior pituitary gland, which is used clinically to treat growth disorders. As a mitogen, one of its key functions is to cause cell growth and reproduction; it also promotes lipolysis to reduce body fat, and causes the growth of all internal organs (apart from the brain). Athletes commonly ingest or inject this anabolic agent to increase their lean muscle mass, strength and physical endurance.

3D model of somatotropin structure

3D model of Somatotropin

Armstrong’s repeated denial of doping and ultimate confession was seen by many as an unforgiveable betrayal to the sport and to his fans, who supported him through his battle with testicular cancer. The web of deception spun by the former hero was one of the most tragic components of the affair; using makeup to conceal injection bruises and lying about incriminating paraphernalia disposed of in roadside skips. But with a combination of a terrible public backlash, a lengthy list of adverse side-effects and a life-long ban from any sport, was doping worth it?

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Veronica Wignall

Veronica is a Biology graduate from the University of Bristol, she is currently an editorial assistant but hopes to move into science media comms! Follow Veronica on Twitter @vronwig

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