Insulin-like growth factor-binding protein-1 inhibits binding of IGF-I on fetal skin fibroblasts but stimulates their DNA synthesis.
Insulin-like growth factor-binding protein-1 (IGFBP-1) was purified from human midtrimester amniotic fluid using monoclonal anti-IGFBP-1 affinity column. Two peaks were obtained in anion exchange chromatography. Both had the same molecular mass of 30 kDa. In monolayer cultures of fetal skin fibroblasts both forms of IGFBP-1 inhibited binding of [125I]IGF-I onto the cells, but amplified the IGF-I-stimulated [3H]thymidine incorporation into the same cells. Radiolabeled IGFBP-1 did not bind to the cells. No detectable IGFBP-1 was released into conditioned medium from the cells, and they contained no specific IGFBP-1 mRNA. Recently we found that the same IGFBP-1 preparation inhibits IGF-I-stimulated [3H]thymidine incorporation into human hyperstimulated granulosa cells. These results show that, depending on target cells, the same protein is capable of either stimulating or inhibiting DNA synthesis.
Koistinen
R
R
Department of Obstetrics and Gynecology, Helsinki University Central Hospital, Finland.
Itkonen
O
O
Selenius
P
P
Seppälä
M
M
D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002846:Chromatography, Affinity; D004261:DNA Replication; D005333:Fetus; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007700:Kinetics; D008970:Molecular Weight; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000302:isolation & purification / Q000378:metabolism*; D017451:Receptors, Somatomedin; D012867:Skin / Q000166:cytology / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism
D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D007334:Insulin-Like Growth Factor I; D013936:Thymidine