title: Characterization of insulin-like growth factor I receptors on human erythroleukemia cell line (K-562 cells).
abstract: Specific insulin-like growth factor I (IGF-I) receptors on a human erythroleukemia cell line (K-562 cells) were identified and characterized. [125I]-IGF-I specifically bound to K-562 cells and the binding was displaced by unlabeled IGF-I in a dose dependent manner, and half maximal inhibition of the binding was observed at 7 ng/ml IGF-I. [125I]IGF-I binding to the cells was displaced by multiplication stimulating activity (MSA) and by porcine insulin, with potencies that were 10, and 100 times less than that of IGF-I, respectively. By an affinity labeling technique, IGF type I receptors were found to be present in the K-562 cells. When the cells were differentiated by hemin (40 microM), specific binding of [125I]IGF-I to the cells was decreased to 56.8 +/- 5.0% of that for undifferentiated cells. Furthermore, at physiological concentration of IGF-I stimulated thymidine incorporation into DNA and increased the number of cells. These data demonstrate that K-562 cells have specific receptors for IGF-I which may be functionally important for these cells, and that the IGF-I binding sites decrease with cell differentiation. This system might be useful in studying the interaction of IGF-I receptors.
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D006427:Hemin / Q000494:pharmacology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism* / Q000473:pathology; D011972:Receptor, Insulin / Q000378:metabolism*; D017451:Receptors, Somatomedin
chemical_list: D017451:Receptors, Somatomedin; D007334:Insulin-Like Growth Factor I; D006427:Hemin; D004247:DNA; D011972:Receptor, Insulin