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. doi: 10.1016/0006-291x(91)90911-p.


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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Cell Division / drug effects
  • Cell Line
  • DNA Replication / drug effects
  • Humans
  • Insulin-Like Growth Factor I / metabolism
  • Insulin-Like Growth Factor I / pharmacology
  • Molecular Sequence Data
  • Osteoblasts / metabolism
  • Osteosarcoma
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / isolation & purification*
  • Receptors, Cell Surface / metabolism
  • Receptors, Somatomedin
  • Sequence Homology, Nucleic Acid


  • Receptors, Cell Surface
  • Receptors, Somatomedin
  • Insulin-Like Growth Factor I