Glycoprotein hormone erythropoietin

Maintenance of red cell volume is critical to having an adequate oxygen supply to the tissues [10]. Healthy individuals finely balance erythropoiesis and erythrocyte loss and maintain constant hematocrit. The glycoprotein hormone erythropoietin is the principal controller of the homeostatic mechanism that links tissue oxygen delivery to red cell production. While hypothesized as early as 1863, unequivocal evidence of erythropoietin was first published in 1953. A few years later, scientists showed that animals subjected to bilateral nephrectomy were unable to mount an erythropoietin response to hypoxia. Indeed, the kidneys produce about 90% of circulating erythropoietin. 

Anemia may occur in patients with chronic renal failure as tlie result of the inability of the kidney to produce erythropoietin. Erythropoietin is a glycoprotein hormone synthesized mainly in the kidneys and used to stimulate and regulate the production of erythrocytes or red blood cells (RBCs). Failure to produce the needed erythrocytes results in anemia Two examples of drug used to treat anemia associated with chronic renal failure are epoetin alfa (Epogen) and darbepoetin alfa (Aranesp). 

Erythropoietin is a glycoprotein hormone that regulates the proliferation, differentiation, and maturation of erythroid cells. The EPO receptor is a member of the class 1 cytokine receptor superfamily. The crystal structure of an EPO-mimetic peptide and the extracellular portion of the... 

Erythropoiesis (A). Blood corpuscles develop from stem cells through several cell divisions. Hemoglobin is then synthesized and the cell nucleus is extruded. Erythropoiesis is stimulated by the hormone erythropoietin (a glycoprotein), which is released from the kidneys when renal O2 tension declines. 

Erythropoietin is a glycoprotein hormone encoded by a gene on the long arm of chromosome 7 (7q) and 90% is produced in the kidney (the remainder in the liver and other sites) in response to hypoxia. The anaemia of chronic renal failure is largely due to failure of the diseased kidneys to make enough erythropoietin. The principal action of the hormone is to stimulate the proliferation, survival and differentiation of erythrocyte precursors. The manufacture of erythropoietin for clinical use became possible when the human gene was successfully inserted into cultured hamster ovary cells. 

Erythropoietin is a glycoprotein hormone that regulates red blood cell production in a feedback loop manner between kidney and bone marrow based on oxygen tension. It consists of 165 amino acids and has a molecular weight of 30,000-34,000 approximately 30% is accounted for by covalently linked carbohydrate. Erythropoietin is produced by the fetal liver and shortly after birth production switches from the liver to the kidney. In the fetus, erythropoietin functions in a paracrine-endocrine fashion because liver is the site of erythropoietin synthesis as well as ery-thropoiesis. The mechanism of this developmental switch is unclear. In the liver, erythropoietin synthesis occurs in... 

Erythropoietin (EPO), a glycoprotein hormone with a molecular mass of 30KDa, is mainly synthesized by the kidney in response to hypoxia. Serum EPO... 

These studies demonstrating a protective effect of sialic acid residues on serum glycoproteins provide an explanation for earlier, conflicting observations about the biological effect of, for example, desialylated erythropoietin, which stimulates erythropoiesis only after direct application to bone-marrow cell-cultures, and not after injection into the blood stream.469 In the latter experiment, only the native, sialylated hormone was active. Rapid clearance and inactivation of follicle-stimulating hormone,470 or interferon,471 after treatment with sialidase may be explained by uptake into liver cells. 

Results obtained" from the reaction of periodate with oligosaccharide structures in erythropoietin are consistent with the proposal that antibodies directed against the recombinant hormone are anti-carbohydrate . That oligosaccharide sequences are involved in the binding of human spermatozoa to a glycoprotein of the zona pellucida, is indicated " " by a marked decrease in binding that accompanies selective periodate oxidation of terminal sialic acid residues of the glycoprotein. 

Erythropoietin (EPO), a hematopoietic cytokine, is a glycoprotein that mediates cytoprotection in brain and spinal cord through activation of multiple signaling pathways (Grasso et al., 2006). In addition, EPO also has a crucial hormonal role in red... 

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