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Updated: Jul 16, 2026

Polyelectrolyte Complex for Heparin Binding Domain Osteogenic Growth Factor Delivery
Published on: August 22, 2016
Insulin-like growth factor binding protein-5 in osteogenesis: facilitator or inhibitor?
Aditi Mukherjee1, Peter Rotwein
1Department of Biochemistry and Molecular Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239-3098, USA.
Abstract:
The insulin-like growth factors (IGFs) play a central role in controlling somatic growth in mammals and exert anabolic effects on most tissues, including bone. IGF action is mediated by the IGF-I receptor and additionally is regulated by six high-affinity IGF binding proteins (IGFBP-1 through IGFBP-6), of which IGFBP-4 and IGFBP-5 are most abundant in bone. The focus of this brief review is on the role of IGFBP-5 in bone biology. IGFBP-5 has been implicated as a pro-osteogenic factor in several studies but conversely has been shown to act as an inhibitor of bone formation, primarily by interfering with IGF actions on osteoblasts. These potentially contradictory effects of IGFBP-5 in bone are further complicated by observations indicating that IGFBP-5 additionally may function in an IGF-independent way, and may have been accentuated by differences in both experimental design and methodology among published studies. Suggestions are made for a more systematic approach to help discern the true roles of IGFBP-5 in bone physiology.
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