Insulin-like growth factor 1 binding protein 3 synthesis by aortic endothelial cells is a function of cell density.
Proliferating bovine aortic endothelial cells in culture do not express the insulin-like growth factor 1 binding protein 3 gene, in contrast to the genes encoding binding proteins 2, 4, 5, and 6. The binding protein 3 gene is activated only at cell confluency with continual transcription thereafter, for at least an eight-day post-confluent period, both in the presence or absence of serum. Secretion of protein product into the medium parallels transcription. DNA synthesis is inversely related to the amount of total insulin-like growth factor 1 binding protein 3 in the culture medium. The addition of anti-binding protein 3 antibody to media significantly increases the rate of DNA synthesis by extensively post-confluent cells. These data suggest (1) aortic endothelial cells are an important source of circulating binding protein 3, (2) binding protein 3 has an inhibitory effect upon the growth of endothelial cells, (3) the triggering of binding protein 3 synthesis after confluency suggests a role in maintaining the growth-arrested monolayer state of the cells in vivo.
Delafontaine
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Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Ku
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Anwar
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Hayzer
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DJ
D000818:Animals; D001011:Aorta; D015152:Blotting, Northern; D015153:Blotting, Western; D002417:Cattle; D002455:Cell Division; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D046508:Culture Techniques / Q000379:methods; D004247:DNA / Q000096:biosynthesis; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism*; D005786:Gene Expression Regulation; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000096:biosynthesis*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D013936:Thymidine / Q000378:metabolism; D014158:Transcription, Genetic
D016895:Culture Media, Serum-Free; D018972:Insulin-Like Growth Factor Binding Protein 3; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D004247:DNA; D013936:Thymidine