Epiao Mechanism of Action

Pharmacotherapeutic group: anti-anaemic. ATC code: B03XA01.
Pharmacology: Pharmacodynamics: Mechanism of action: Erythropoietin (EPO) is a glycoprotein hormone produced primarily by the kidney in response to hypoxia and is the key regulator of red blood cell (RBC) production. EPO is involved in all phases of erythroid development and has its principal effect at the level of erythroid precursors. After EPO binds to its cell surface receptor, it activates signal transduction pathways that interfere with apoptosis and stimulates erythroid cell proliferation. Recombinant human EPO (epoetin alfa), expressed in Chinese hamster ovary cells, has a 165 amino acid sequence identical to that of human urinary EPO; the 2 are indistinguishable on the basis of functional assays. The apparent molecular weight of erythropoietin is 32,000 to 40,000 dalton.
Erythropoietin is a growth factor that primarily stimulates red cell production. Erythropoietin receptors may be expressed on the surface of a variety of tumour cells.
Pharmacokinetics: After subcutaneous administration, absorption of erythropoietin is slow from the injection site. Increase of serum concentration of Recombinant Human Erythropoietin can be observed 2 hours after administration and the peak concentration is achieved 18 hours post dosing. Bone marrow is the specific absorption organ of Recombinant Human Erythropoietin, and it is also absorbed in liver and kidneys. Recombinant Human Erythropoietin is mainly metabolized in the liver. Results from animal (rat) studies also indicate that the kidneys, bone marrow and spleen can also metabolize a small portion of Recombinant Human Erythropoietin. Recombinant Human Erythropoietin is not mainly excreted from the kidney. In anemia patients treated with Recombinant Human Erythropoietin, less than 10% of non-degraded Recombinant Human Erythropoietin is excreted from the kidney.
Toxicology: Erythropoietin is a glycoprotein which is excreted from the kidney and stimulates the differentiation and proliferation of erythroid progenitors in bone marrow. The in vitro and in vivo biological activities of recombinant human erythropoietin are identical to the natural endogenous erythropoietin. Pharmacodynamic studies demonstrate that Epoetin Alfa (EPIAO) can increase the colony formation of CFU-E, and result in significant therapeutic benefits to anemia patients caused by chronic renal failure.