The regulation of type-I collagen synthesis by insulin-like growth factor-I in human osteoblast-like SaOS-2 cells.
The effect of insulin-like growth factor-I on collagen synthesis was studied using cultured human osteoblast-like SaOS-2 cells by measuring the incorporation of tritiated L-proline into immunoprecipitable type-I collagen. Tritiated L-proline incorporation into collagen was significantly stimulated by insulin-like growth factor-I in a time- and concentration-dependent manner. Unlabelled L-proline and alpha-(methylamino) isobutyric acid inhibited either the influx into cells, or the incorporation into collagen, of tritiated L-proline. The increase in incorporation of tritiated L-proline was significantly reduced by cycloheximide and actinomycin D. L-Proline incorporation into collagen was also stimulated by insulin-like growth factor-II, insulin-like growth factor-I analogues and insulin. The insulin-like growth factor-I-stimulated L-proline incorporation was inhibited by one of its binding proteins, insulin-like growth factor binding protein-4, in a concentration-dependent manner.
Kudo
Y
Y
Department of Obstetrics and Gynecology, Tokyo Women's Medical College, 8-1 Kawada, Shinjuku, Tokyo 162, Japan.
Iwashita
M
M
Iguchi
T
T
Takeda
Y
Y
D002460:Cell Line; D003094:Collagen / Q000096:biosynthesis*; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D006801:Humans; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D009994:Osmolar Concentration; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D011392:Proline / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013002:Somatomedins / Q000494:pharmacology; D013997:Time Factors
D018974:Insulin-Like Growth Factor Binding Protein 4; D011500:Protein Synthesis Inhibitors; D013002:Somatomedins; D003609:Dactinomycin; D007334:Insulin-Like Growth Factor I; D003094:Collagen; D003513:Cycloheximide; D011392:Proline