Erythropoietin or Hematopoietin, unlike most of other steroids, is a glycoprotein i.e. a peptide hormone with a carbohydrate moiety, which produced and released naturally from the peritubular fibroblasts of the cortex in our kidneys. It is a known cytokine i.e. a signaling hormone known to be involved in cell-cell communication.

Erythropoietin and RBCs:

Erythropoietin is known to stimulate the production of red blood cells (RBCs) and increase the hematocrit i.e. the ratio of the volume occupied by packed red blood cells to the volume of the whole blood or the percentage of blood by volume composed of erythrocytes, as measured by a hematocrit instrument. A good example of erythropoietin in action is the effect of increased altitude on the blood oxygen concentration. As the altitude progressively increases, the atmospheric pressure decreases causing a resultant decrease in the available oxygen needed for respiration.

Neuro-protective Action of Erythropoietin:

Various studies that have been conducted to evaluate the anti-apoptotic mechanisms to account for the neuro-protective actions of erythropoietin suggest its short latency protective effects by inhibition of neuronal apoptosis after cerebral ischemia & other brain injuries. The neurotrophic actions suggest that there may be longer-latency effects or erythropoietin as well.

Wound Healing and Erythropoietin:

Some studies have investigated the role of the hematopoietic cytokine erythropoietin (EPO) during wound healing, the physiological response to tissue injury, and found that the local, exogenous recombinant erythropoietin administration into the fibrin matrix significantly increases the granulation tissue formation in a dose-dependent manner.

Side Effects of Erythropoietin:

As with most ergogenic substances, there is usually a downside associated with the use of erythropoietin. As the hematocrit increases, the other main components of blood plasma decrease. It may lead to polycythemia in which the blood becomes thicker - almost sludgy; making it increasingly difficult for the heart to pump it through the body. The increased viscosity of the blood also increases blood pressure and the risk of clotting incidents like a stroke.

Misuse of Erythropoietin in Sports:

With the recent advances in genetic engineering and recombinant DNA technology, synthetic or recombinant Erythropoietin (rEPO) has become readily available and has been utilized extensively by athletes as an ergogenic aid. The rationale behind such use of erythropoietin is that if you increase the oxygen-carrying ability of the blood above normal levels, then the muscles shall receive more oxygen and are expected to be able to perform better for a longer periods of time, thereby significantly improving performance.