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Insulin-like growth factor I and bone: from mouse to man
W G Beamer1, L R Donahue, C J Rosen
1The Jackson Laboratory, Bar Harbor, Maine, USA.
Summary
Genetic factors influence serum insulin-like growth factor I (IGF-I) levels and bone acquisition. Researchers identified regulatory loci for IGF-I and linked them to bone mineral density in mice, advancing understanding of related disorders.
Area of Science:
- Genetics
- Endocrinology
- Bone Biology
Background:
- Serum insulin-like growth factor I (IGF-I) is influenced by growth hormone (GH), nutrition, and hormones.
- Heritable factors also regulate circulating IGF-I and its tissue-specific gene expression.
- Serum IGF-I concentration strongly correlates with bone acquisition in mice and humans.
Purpose of the Study:
- To investigate non-GH-dependent factors regulating serum IGF-I.
- To identify genetic determinants of serum IGF-I levels.
- To establish the relationship between IGF-I regulatory loci and bone mineral density quantitative trait loci.
Main Methods:
- Performed intercrosses between two inbred mouse strains with differing serum IGF-I levels.
- Mapped quantitative trait loci (QTL) for serum IGF-I.
- Assessed the relationship between IGF-I QTL and bone mineral density QTL.
Main Results:
- Identified specific regulatory loci controlling serum IGF-I levels in mice.
- Established a genetic link between serum IGF-I regulation and bone mineral density.
- Demonstrated the involvement of non-GH-dependent genetic factors in IGF-I regulation and bone acquisition.
Conclusions:
- Genetic loci significantly influence serum IGF-I levels independently of GH.
- These genetic factors play a role in bone mass acquisition.
- Mapping these QTLs enhances understanding of IGF-I related disorders and bone metabolism.