A novel human insulin-like growth factor binding protein secreted by osteoblast-like cells.
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Andress DL, Birnbaum RS
A novel human insulin-like growth factor binding protein secreted by osteoblast-like cells.
Biochem Biophys Res Commun. 1991 Apr 15;176(1):213-8.
- PubMed ID
- 1850257 [ View in PubMed]
- Abstract
Insulin-like growth factor binding proteins (IGFBPs) modulate the cellular action of the insulin-like growth factors. Inhibition or enhancement of IGF effects by these cell-secreted binding proteins have been described. We have purified two IGFBPs (23 and 29 kDa) from media conditioned by U-2 human osteosarcoma cells using ligand-affinity chromatography and reversed phase HPLC. N-terminal amino acid analysis of the 23 kDa protein revealed a unique sequence with variable homology to IGFBPs 1-4. The 29 kDa IGFBP was found to be nearly identical to a recently reported IGFBP. Because the affinity purified U-2 IGFBPs enhanced IGF-I-stimulated osteoblast mitogenesis, we suggest that one or both of these binding proteins enhance IGF action in bone.