Scholz, H., Baier, W., Ratcliffe, P., Eckardt, K., Zapf, J., Kurtz, Armin und Bauer, C.
(1992)
Insulin-like growth factors decrease oxygen-regulated erythropoietin production by human hepatoma cells (Hep G2).
The American journal of physiology. Cell pyhsiology 263 (2 Pt 1), C474-C479.
Veröffentlichungsdatum dieses Volltextes: 04 Dez 2012 13:52Zum PubMed-Eintrag dieses Artikels
Zusammenfassung
We examined the effects of insulin-like growth factors (IGFs) and insulin on erythropoietin (EPO) production by human hepatoma cells (Hep G2). Compared with normoxia (20% O2), EPO production by Hep G2 cells during a 72-h incubation was stimulated fivefold by exposure to low oxygen tension (1% O2) and nearly threefold by exposure to cobalt chloride (100 microM). IGF-I caused a ...
Zusammenfassung
We examined the effects of insulin-like growth factors (IGFs) and insulin on erythropoietin (EPO) production by human hepatoma cells (Hep G2). Compared with normoxia (20% O2), EPO production by Hep G2 cells during a 72-h incubation was stimulated fivefold by exposure to low oxygen tension (1% O2) and nearly threefold by exposure to cobalt chloride (100 microM). IGF-I caused a concentration-dependent attenuation of EPO formation under normoxic conditions and inhibited (maximally 50%) EPO production stimulated by either low oxygen tension or cobalt [half-maximal effect (ED50) approximately 5 nM]. The increase of EPO mRNA levels in response to hypoxia was significantly reduced by IGF-I. Similarly to IGF-I, IGF-II (ED50 approximately 8 nM) and insulin (ED50 approximately 80 nM) also inhibited EPO formation in Hep G2 cells. IGF-I (100 pM-100 nM) stimulated the incorporation of radiolabeled alanine as a measure for total protein synthesis, 3H-labeled thymidine incorporation into DNA, and glycogen synthesis at 20 and 1% O2 in a concentration-dependent fashion. IGF-I exhibited a high affinity for the IGF-I receptor (apparent Kd approximately 3 nM). Unlabeled insulin was greater than 100-fold less potent than IGF-I in competing for 125I-IGF-I binding (apparent Kd approximately 360 nM). Conversely, insulin bound to the insulin receptor with high affinity (apparent Kd approximately 0.3 nM), whereas IGF-I was less than 1% as potent in competing for 125I-insulin binding. In summary, IGFs and insulin exert a negative control function on oxygen-regulated EPO production in Hep G2 cells. The inhibitory effect of IGFs and insulin on EPO formation appears to be mediated via the IGF-I receptor.
Bibliographische Daten exportieren
| Dokumentenart: | Artikel |
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| Datum: | 1992 |
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| Institutionen: | Biologie und Vorklinische Medizin > Institut für Physiologie > Prof. Dr. Armin Kurtz |
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| Identifikationsnummer: | |
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| Klassifikation: | | Notation | Art |
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| Animals | MESH | | Culture Media | MESH | | Dose-Response Relationship, Drug | MESH | | Erythropoietin/biosynthesis | MESH | | Humans | MESH | | Insulin/pharmacology | MESH | | Insulin-Like Growth Factor I/pharmacology | MESH | | Insulin-Like Growth Factor II/pharmacology | MESH | | Liver Neoplasms/pathology | MESH | | Liver Neoplasms, Experimental/pathology | MESH | | Oxygen/pharmacology | MESH | | Receptor, Insulin/metabolism | MESH | | Receptors, Cell Surface/metabolism | MESH | | Receptors, Somatomedin | MESH | | Somatomedins/pharmacology | MESH | | Tumor Cells, Cultured | MESH |
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| Dewey-Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie
600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin |
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| Status: | Veröffentlicht |
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| Begutachtet: | Ja, diese Version wurde begutachtet |
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| An der Universität Regensburg entstanden: | Unbekannt / Keine Angabe |
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| Dokumenten-ID: | 26946 |
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