ron19 said:
We're talking about 1999 here if I'm not mistaken. What happened in 2000-2005 ? Any more "evidence"?. In my view LA is THE supreme athlete & master tactician.
According to the prescribing informatin for the product:
Erythropoietin is a glycoprotein which stimulates red blood cell production. It is produced in the kidney and stimulates the division and differentiation of committed erythroid progenitors in the bone marrow. EPOGEN® (Epoetin alfa), a 165 amino acid glycoprotein manufactured by recombinant DNA technology, has the same biological effects as endogenous erythropoietin. It has a molecular weight of 30,400 daltons and is produced by mammalian cells into which the human erythropoietin gene has been introduced. The product contains the identical amino acid sequence of isolated natural erythropoietin.
I added the bold print so that no one misses the fact that erythropoietin is naturally produced by the body, and the substance that LA was supposed to have used is identical to the natural product. Erythropoietin is produced by the kidney in response to low oxygen saturation in the blood. Erythropoietin stimulates the production of red blood cells. If one has healthy kidneys, which I would assume most of the top riders do, anything that decreases the amount of oxygen reaching the kidney will cause the kidney to produce more erythropoietin.
I would think that exercising hard, which causes the muscles to remove oxygen from the red blood cells, would result in less oxygen reaching the kidney. I also would think that exercising at high altitudes (Alps? Pyrenees?) would further reduce the amount of oxygen that reaches the kidney. The bottom line is that all riders should have higher levels of erythropoietin than normal. Riders whose muscles are more efficient at removing oxygen from the blood will have even higher levels of erythropoietin than other riders.
Erythropoietin is a protein - a very large molecule. Molecules this large are too large to be filtered through the glomerulus, and therefore, are not normally excreted in the urine.
All of this raises three questions in my mind:
1. How does one set limits for a naturally occurring substance in athletes, who by the nature of their activity, are expected to have higher than normal levels of this substance in their blood?
2. Why would one look for a 165 amino acid glycoprotein in the urine, when it is not normally excreted in the urine?
3. How does a glycoprotein get into the urine of a patient who has normal kidneys, when normal kidneys would not filter out a molecule this large?