A2 Biology Topic 7 Performance enhancing drugs

Banned substances and practicesAnabolic steroidsHormones and releasing factorsBeta-2 agonistsHormone agonistsDiureticsBlood dopingGene dopingStimulantsNarcoticsBeta blockersIs 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 hormonesPass through the plasma membrane and stimulate protein synthesis

Steroid hormonesOther steroid molecules

Mechanism of action of steroid hormones:cell surface membranesteroid hormonereceptorHormone enters cell and binds with receptorhormone-receptor complexenters nucleusnuclear membraneComplex binds to DNA and acts as a transcription factorSwitches on a gene for synthesis of a protein

TestosteroneStimulates protein synthesis

Results in bigger and stronger muscles

Anabolic steroidstestosteronenandroloneNatural testosterone is quickly broken down. Testosterone is modified to produce drugs that remain for longer in the body These synthetic anabolic steroids are illegal.

Side-effects of using anabolic steroids21 year old body builder: A and B Severe acne conglobata C After 8 weeks off steroids and with antibiotics

Infertility due to disruption of normal hormone production:- disrupted menstrual cycle - reduced sperm productionimpotence In addition: - liver damage- high blood pressure- heart attacks- increased aggression

Peptide hormonesPeptide 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 hormonereceptorcell surface membraneInactive secondary messenger eg. cAMPSecondary messenger activated: initiates a protein kinase cascadeenters nucleusacts as a transcription factor which switches on gene for a specific protein

ErythropoietinErythropoietin 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 erythropoeitinIncreases 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 erythropoietinExcess 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 drugsCreatine is not banned:Classed as a nutritional supplementCan cause kidney damage and high blood pressureErythropoietin is banned:Is a naturally occurring hormoneCan cause strokes and heart attacksBlood doping banned:Donating, storing and transfusing own blood before competitionHigh altitude training not banned:Increases number of red blood cells.Caused by natural increase in erythropoietin production.Is everything acceptable in the pursuit of sporting excellence?Isnt it the choice of the athlete to risk using drugs or not?Do use of performance- enhancing drugs improve or ruin competition?Are there circumstances when drug use is acceptable?Problems with deciding on what is illegal:Ethical questions:

EssayRead 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.