title: Action of erythropoietin in vitro on rabbit reticulocyte membrane Ca2+-ATPase activity.
abstract: The mechanism of action of erythropoietin is thought to require specific interaction with the target cell surface and involve alteration of cellular calcium metabolism. Using the rabbit reticulocyte membrane as a model of the immature red cell membrane, we investigated the effects of human recombinant erythropoietin on membrane Ca2+-ATPase (calcium pump) activity in vitro. Erythropoietin in a concentration range of 0.025 to 3.0 U/ml progressively decreased membrane Ca2+-ATPase activity by up to 64% (P less than 0.01). These concentrations have been shown by others to stimulate in vitro erythroid growth. The action of erythropoietin on reticulocyte Ca2+-ATPase required an incubation time of 1 h before enzyme assay for maximum effect and was neutralized by antierythropoietin antiserum. Other nonhemopoietic growth factors (epidermal growth factor, insulin) had no effect in this assay. Ca2+-ATPase activity of membranes prepared from rabbit mature red blood cells was not inhibited by erythropoietin. The novel effect of erythropoietin on reticulocyte membrane Ca2+-ATPase activity is a mechanism by which erythropoietin can influence cellular Ca2+ metabolism.
mesh_terms: D000818:Animals; D000252:Calcium-Transporting ATPases / Q000097:blood*; D002147:Calmodulin / Q000494:pharmacology; D004910:Erythrocyte Membrane / Q000201:enzymology; D004921:Erythropoietin / Q000494:pharmacology*; D066298:In Vitro Techniques; D011817:Rabbits; D011994:Recombinant Proteins / Q000494:pharmacology; D012156:Reticulocytes / Q000201:enzymology*; D013997:Time Factors
chemical_list: D002147:Calmodulin; D011994:Recombinant Proteins; D004921:Erythropoietin; D000252:Calcium-Transporting ATPases