Binding of iodinated erythropoietin to rat bone marrow cells under normal and anemic conditions

Journal Article · Wed Feb 01 04:00:00 EST 1989 · Exp. Hematol.; (United States)

OSTI ID:6465157

Akahane, K; Tojo, A; Fukamachi, H; Kitamura, T; Saito, T; Urabe, A; Takaku, F

Specific binding sites for erythropoietin (Epo) were shown in normal and anemic rat bone marrow cells using (125I)labeled human recombinant Epo. When rats were treated once or several times with phenylhydrazine or malotilate, or by phlebotomy, the serum Epo level determined by RIA began to increase rapidly. Thereafter, both the number of erythroid colony-forming unit (CFU-E)-derived colonies and the Epo binding capacity of bone marrow cells increased almost simultaneously in response to induced anemic states, suggesting that the amount of Epo binding in bone marrow cells may reflect in vivo erythropoiesis. Scatchard analysis of the binding data from normal rats revealed the presence of a single class of binding sites (Kd = 0.18 +/- 0.04 nM, 38 +/- 5 sites/cell). In anemic states, the apparent average receptor number per cell increased (52-62 sites/cell) without changing in binding affinity toward Epo. Furthermore, (125I)Epo was cross-linked to the cell surface molecule of approximately 165 kd in nonreducing conditions and 75 kd in reducing conditions. Autoradiographic analysis indicated that Epo receptors were distributed on immature erythroid cells. Proerythroblasts were the most heavily labeled, whereas orthochromatic erythroblasts and cells of myeloid and lymphoid lineages were not labeled. Calculations based on Scatchard and autoradiographic analysis showed that proerythroblasts have 390 receptor sites per cell, twice as many as basophilic or polychromatophilic erythroblasts have. These results are consistent with the stage-specific action of Epo in physiological differentiation of erythroid cells.

• Research Organization: Daiichi Seiyaku Company Limited, Tokyo (Japan)
• OSTI ID: 6465157
• Journal Information: Exp. Hematol.; (United States), Journal Name: Exp. Hematol.; (United States) Vol. 17:2; ISSN EXHMA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
550901 -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANEMIAS
ANIMAL CELLS
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BONE MARROW CELLS
CHEMICAL REACTIONS
COLONY FORMATION
CONNECTIVE TISSUE CELLS
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
DISEASES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ERYTHROPOIETIN
HEMATOLOGIC AGENTS
HEMIC DISEASES
IMMUNOASSAY
IMMUNOLOGY
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MITOGENS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PATHOGENESIS
POLYMERIZATION
PROTEINS
RADIOASSAY
RADIOIMMUNOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SOMATIC CELLS
SYMPTOMS
TRACER TECHNIQUES
VERTEBRATES