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ERYTHROPOIETIN ERYTHROPOIETIN
By - Sahithi Sahithi
INTRODUCTION INTRODUCTION Erythropoietin is also called as Hemopoietin
or Erythrocyte Stimulating Factor
or Erythropoiesis Stimulating Agent.
HISTORYHISTORY
In 1906, Paul Carnot, a professor of medicine of Paris
with his assistant DeFlandre proposed that “Hormones
regulate the production of red blood cells”. . Eva Bonsdorff coined the name for the hemopoietic
substance as ‘ERYTHROPOIETIN’ERYTHROPOIETIN’. Lin in 1985 , isolated the erythropoietin gene of
human being from a genomic phage library. 1989 , US food and Drug Administration approved the
use of EPOGEN.
STRUCTURE
Erythropoietin is a Glycoprotein.
Protiens – 74%
carbohydrates – 26%
It contains 165 amino acid residues
with a molecular weight of 34,000.
Half life is 5hrs.
SOURCE In fetus & neonate, the major site of formation of
erythropoietin is in liver.
In adults, there are two sources which
involve in the production of
erythropoietin.
Renal source – 85%
Hepatic sources – 15%
ERYTHROPOIETIN RECEPTOR AND ERYTHROPOIETIN RECEPTOR AND MECHANISM OF ACTIONMECHANISM OF ACTIONErythropoietin ReceptorErythropoietin Receptor:- The receptor for erythropoietin is a linear protein with
a single transmembrane domain that is a member of the cytokine receptor superfamily.
Mechanism of action:-Mechanism of action:- Erythropoietin binds to the receptor on the target cells.
The receptor has tyrosine kinase activity and it activates a cascade of serine and threonine kinase, inhibiting apoptosis of red cells resulting in growth and development of target cells.
FUNCTIONS
Important effect of erythropoietin is to stimulate the
production of proerythroblasts from hematopoietic
stem cells in the bone marrow.
FUNCTIONS OTHER THAN HAEMOPOIESIS
Increase iron absorption. Vasoconstriction dependent hypertension. Angiogenesis . Proliferation of smooth muscle fibers. Epo can also effects the mood. It promotes haemoglobin synthesis by
increasing globin synthesis and potentiating δ amino levulinic acid synthetase.
Epo binds with EpoR receptors on red cells and induce jak2 signalling cascade.
FACTORS INFLUENCING FACTORS INFLUENCING ERYTHROPOIETIN PRODUCTIONERYTHROPOIETIN PRODUCTION
Factors increases erythropoietin secretions.Factors increases erythropoietin secretions.Hypoxia.Hormones.Nucleotides.
Factors Decreases Erythropoietin Secretions.Factors Decreases Erythropoietin Secretions.OestrogenAdenosine antagonist.
HYPOXIA HYPOXIA Hypoxia is a potent stimulator of Erythropoietin secretion from Kidney.
HypoxiaHypoxia HypoxiaHypoxia
ERYTHROPOIETINERYTHROPOIETIN
ERYTHROPOIESIS
(Haemopoetic Stem Cells In Bone Marrow)
Stimulates “Hypoxia inducible factors present in kidney”
HormonesHormones Androgens : specially “TESTOSTERONE”. They
increases the no. of stem cells in bone marrow,
stimulates the production of erythropoietin.
Thyroid Hormones: “ TH ” alternate the gene
expression and also stimulates erythropoietin by
increasing renal tissue hypoxia.
Nucleotides: cAMP , NAD and NADP increases Epo
secretion.
Products released after destruction of RBC after
120 days of life span are also stimulates Epo
secretion.
FACTORS DECREASES ERYTHROPOIETIN FACTORS DECREASES ERYTHROPOIETIN SECRETIONSSECRETIONS
Estrogen: decrease the erythropoietin
secretions by inhibiting stem cell response.
Adenosine antagonist.
INACTIVATION INACTIVATION
Principle site of inactivation of
erythropoietin is in liver.
RECOMBINANT ERYTHROPOIETIN
A recombinant erythropoietin which is produced
in animal cells for therapeutic use.
They are
1.Epoetin α.
Epogen
Procit
Aransep …Etc.
USES OF RE COMBINAT EPO
To treat patients with anaemia Chronic renal disease. Crohn’s disease. Cancer patients under chemotherapy and
radiation.
APPLIED ASPECTS
Erythropoietin is also used to stimulate RBC
production in individuals who are banking a supply of
their own blood in preparation for autologous
transfusions during elective surgery.
Blood doping : Due increase muscle ability by
increase
the delivery of oxygen, Epo is misused by athletes.