A2 Biology Topic 7 Performance enhancing drugs
Banned substances and practices
Anabolic steroids
Hormones and releasing factors
Beta-2 agonists
Hormone agonists
Diuretics
Blood doping
Gene doping
Stimulants
Narcotics
Beta blockers
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:
cell surface membranesteroid hormone
receptor
Hormone enters cell and binds with receptor
hormone-receptor complex
enters nucleus nuclear membrane
Complex binds to DNA and acts as a
transcription factor
Switches on a gene for synthesis of a protein
Testosterone
Stimulates protein synthesis
Results in bigger and stronger muscles
Anabolic steroids
testosterone
nandrolone
Natural 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 steroids
21 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 production-impotence
In addition:- liver damage- high blood pressure- heart attacks- increased aggression
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
enters nucleus
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
Creatine is not banned:Classed as a nutritional supplementCan cause kidney damage and high blood pressure
Erythropoietin is banned:Is a naturally occurring hormoneCan cause strokes and heart attacks
Blood doping banned:Donating, storing and transfusing own blood before competition
High 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?
Isn´t 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:
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.