A2 Biology Topic 7 Performance enhancing drugs Banned substances and practices Anabolic steroids Stimulants Hormones and releasing factors Beta-2 agonists Narcotics Beta blockers Hormone agonists Diuretics Blood doping Gene doping Is it an infringement of athletes human rights to be required to give blood and urine samples? Page reference: 178-179 Edexcel A2 Biology (concept) textbook Steroid hormones Pass through the plasma membrane and stimulate protein synthesis Steroid hormones Other steroid molecules Mechanism of action of steroid hormones: steroid hormone cell surface membrane Hormone enters cell and binds with receptor Complex binds to DNA and acts as a transcription factor receptor nuclear membrane enters nucleus hormone-receptor complex Switches on a gene for synthesis of a protein Testosterone Stimulates protein synthesis Results in bigger and stronger muscles Anabolic steroids Natural testosterone is quickly broken down. testosterone Testosterone is modified to produce drugs that remain for longer in the body These synthetic anabolic steroids are illegal. nandrolone Side-effects of using anabolic steroids Infertility due to disruption of normal hormone production: - disrupted menstrual cycle - reduced sperm production -impotence In addition: - liver damage - high blood pressure - heart attacks - increased aggression 21 year old body builder: A and B Severe acne conglobata C After 8 weeks off steroids and with antibiotics Peptide hormones Peptide hormones do not enter the cell. They bind to receptors on the cell surface membrane. They also act to switch genes on or off. Human erythropoietin Mechanism of action of peptide hormones: peptide hormone receptor cell surface membrane Inactive secondary messenger eg. cAMP Secondary messenger activated: initiates a protein kinase cascade acts as a transcription factor which switches on gene for a specific protein Erythropoietin Erythropoietin is synthesised in the kidneys Causes the synthesis of enzymes required for synthesis of red blood cells (erythrocytes) in bone marrow. Useful for treating anaemia. Use of erythropoeitin Increases number of blood cells and therefore enhances oxygen supply to muscles. Improvement of 10% in aerobic performance Use is popular with endurance athletes and cyclists Side-effects of overuse of erythropoietin Excess of red blood cells can lead to strokes and heart attacks . Attacks most common at night due to low heart rate. Thought to have caused the unexpected deaths of 18 european cyclists between 1987 1991 . Abuse difficult to prove as it is naturally occurring. Ethics of performance-enhancing drugs Problems with deciding on what is illegal: Ethical questions: Creatine is not banned: Classed as a nutritional supplement Can cause kidney damage and high blood pressure Is everything acceptable in the pursuit of sporting excellence? Erythropoietin is banned: Is a naturally occurring hormone Can cause strokes and heart attacks Isn´t it the choice of the athlete to risk using drugs or not? Blood doping banned: Donating, storing and transfusing own blood before competition Do use of performanceenhancing drugs improve or ruin competition? High altitude training not banned: Increases number of red blood cells. Caused by natural increase in erythropoietin production. Are there circumstances when drug use is acceptable? Essay Read pages 182 – 183 (of concept approach textbook) and answer question 2 on page 183: Describe an absolutist and a relativist ethical position on the proposal to set a maximum total red blood cell count for athlete rather than measure erythropoietin levels.