See also: EPO and altitude training
erythropoietin
Erythropoietin, known to most as EPO, is a glycoprotein hormone (consisting of 193 amino acids whose first 27 are lost at the time of secretion) that regulates the production of red blood cells (erythropoiesis). It is mainly synthesized by kidney cells and to a small extent by the liver which becomes the main producer only during fetal life. The use of erythropoietin in the medical field allows treating some types of anemias, such as that due to chronic renal failure.
What are its functions?
After being introduced into the circulation, erythropoietin interacts with specific receptors (Epor) present in the bone marrow, the most important hematopoietic organ in the adult. In particular, the erythropoietin-receptor binding triggers a series of processes that lead to the formation of new red blood cells.
In our body there are no reserves of erythroprotein and its synthesis varies in relation to the metabolic demands. In particular, the production of EPO is regulated by the presence of oxygen in the tissues and to a minimum part by its concentration in the serum. If the tissues do not receive enough oxygen, the kidneys increase the secretion of erythropoiesin and vice versa. It is enough to close a subject for a few hours in a room with a reduced presence of oxygen to significantly increase the production of erythropoietin.
Also some hormones like testosterone and thyroid hormones intervene in this synthesis process.
Normal levels of erythropoietin in the blood are about 2-25 mU / ml, but can increase 100-1000 times as a response to hypoxia
Synthetic erythropoietin
The gene that regulates erythropoietin production was first isolated in 1985.
EPO can be synthesized in the laboratory using the recombinant DNA technique. This method, fairly recent but expensive, allows a specific gene to be extracted from the DNA of a cell and inserted into another cell that will produce large quantities of pure substance encoded by that gene (in this case the ego).
Differences between endogenous and synthetic erythropoietin
Red blood cells are the result of a long process of cell division and differentiation.
Thanks to its function, erythropoietin is able to regulate these steps by selecting and maturing only the functional cells.
Erythropoietin produced in the laboratory is unable to make this selection. Consequently, following its administration, even imperfect cells with a greater risk of haematic and tumor pathologies are synthesized and released into the circulation.
Why do athletes use them?
A higher concentration of red blood cells in the blood improves oxygen transport to the tissues. Erythropoietin is therefore mainly used in endurance sports to promote cellular aerobic processes and ensure greater resistance to fatigue.
Although some studies have attributed erythropoietin to modest anabolic properties (muscle cell repair and increased lean mass) its use in power sports is limited as it is not very effective in improving performance.
EPO and doping: dangers and side effects
As is known, red blood cells (GRs) carry oxygen to tissues and endurance sports, such as cycling, cross-country skiing, etc., the demands on oxygen are very high. For some time, therefore, methods have been investigated to increase the production of red blood cells in order to improve sports performance. The most recent strategy is based on the stimulatory role of erythropoietin on the synthesis of red blood cells by the bone marrow.
Erythropoietin of exogenous origin (synthetic) is much more harmful to health than the endogenous secreted by the kidney.
We have already seen how the administration of this substance causes the production of abnormal red blood cells and increases the risk of developing blood and tumoral pathologies (leukemia). However, there is also another reason why synthetic erythropoietin is very dangerous for the health of the athlete: the increase in red blood cells decreases the fluidity of the blood, increasing the solid or corpuscular part (hematocrit). This increase in viscosity causes an increase in blood pressure (hypertension) and facilitates the formation of thrombi which, once formed, can occlude blood vessels (thrombosis). This risk increases considerably in the event of dehydration, as is usually the case in endurance races.
The most serious side effects of this substance include cardiac arrhythmias, sudden death and brain damage (stroke).
