Erythropoietin induces rapid increases in intracellular free calcium in human bone marrow cells.
Elevation of intracellular free calcium (Ca++) is an early activation event that occurs as a result of ligand binding in several human cell systems. In this report, erythropoietin, the major hormone governing erythroid differentiation, was found to elicit an increase in Ca++ in human bone marrow mononuclear cells. Two chelators of intracellular calcium, quin 2 and the more specific and sensitive analogue, fura-2, were used to characterize the response evoked by both recombinant and native hormone. Erythropoietin caused a rapid, dose-dependent rise (within seconds) in Ca++ in bone marrow mononuclear cells, which could be prevented by preincubation of hormone with a rabbit erythropoietin antiserum. The erythropoietin response did not occur in purified populations of T- or B-lymphocytes. These studies suggested that increased Ca++ on erythropoietin binding may be an early transmembrane signal in hormone action.
Mladenovic
J
J
Department of Medicine, University of Minnesota, Minneapolis.
Kay
N E
NE
D000634:Aminoquinolines; D001402:B-Lymphocytes / Q000378:metabolism; D001572:Benzofurans; D001853:Bone Marrow / Q000378:metabolism; D001854:Bone Marrow Cells; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002614:Chelating Agents; D004921:Erythropoietin / Q000494:pharmacology*; D005456:Fluorescent Dyes; D016257:Fura-2; D006801:Humans; D013601:T-Lymphocytes / Q000378:metabolism
D000634:Aminoquinolines; D001572:Benzofurans; D002614:Chelating Agents; D005456:Fluorescent Dyes; D004921:Erythropoietin; C035739:Quin2; D002118:Calcium; D016257:Fura-2