S4. Hormone and metabolic modulators
Anti-estrogenic substances act in various ways to prevent the conversion of testosterone, the male sexual hormone, into the female hormone estrogen.
The use of anti-estrogens can lead to a number of symptoms, including hot flashes, vaginal bleeding, abdominal pain, headache, vision impairments and an increased risk of thrombosis.
Anti-estrogens are used in the treatment of women with breast cancer and other hormone-dependent tumors as well as osteoporosis, and in order to stimulate ovulation. No medical use exists for the treatment of men.
Misuse in sports:
Anti-estrogens have been on the WADA Prohibited List since 2001. The ban, which originally applied only to men, was extended in 2005 to include women. Misuse of these substances in sports is not primarily aimed at enhancing performance but rather at suppressing the commonly recognized side effects of anabolic agents, such as breast growth among men. The side effects are masked in an attempt to conceal the misuse. It is speculated that anti-estrogens increase testosterone levels in the blood, a notion that has not yet been unequivocally corroborated, however.
Insulin is produced in the pancreas and is responsible for regulating sugar metabolism. This hormone has been on the doping list since 1999.
Insulin plays a vital role in the functioning of the human body by transporting glucose, the body's main source of energy, from the blood to the muscles. A higher level of insulin is released in response to the ingestion of food in order to facilitate cell absorption of glucose and amino acids. Insulin increases the synthesis of glycogen in the liver, stimulates the production of fats from glucose and inhibits the conversion of proteins to glucose.
An overdose of insulin can lead to a lower than normal level of blood glucose, or hypoglycemia, resulting in symptoms such as heart palpitations, restlessness, trembling and perspiration. A hypoglycemic coma can occur at very low blood glucose levels. Insulin must be administered by injection, which may result in changes in the subcutaneous tissue (lipodystrophy).
Taking insulin may be necessary to treat diabetic disorders. While the insulin used in treatment was previously obtained from cows and pigs (i.e. bovine and porcine insulin), nowadays it is synthesized using genetic engineering techniques.
Misuse in sports:
Insulin triggers a number of anabolic (building up) processes in metabolism, including synthesis of glycogen, lipids and proteins. Originally used mainly in strength sports, insulin has in the meantime come to be used in endurance sports as well. Insulin and carbohydrates are combined in specific preparation for competition in order to store a greater amount of energy in muscle cells. Yet experts question the capability of insulin to actually enhance performance. Insulin is prohibited in- and out-of-competition. An athlete needing to take insulin can apply for a therapeutic use exemption (TUE).