Beta 2-microglobulin enhances insulin-like growth factor I receptor levels and synthesis in bone cell cultures.
Beta 2-Microglobulin (beta 2m), a component of the major histocompatibility complex in chordates, has growth factor-like activity for cultured rat cells. We presently describe interactions between beta 2m and insulin-like growth factor I (IGF I) in osteoblast-enriched cultures. beta 2m increased DNA synthesis and was synergistic with IGF I. Affinity labeling revealed that beta 2m enhanced IGF I receptor number, and Northern analysis and radioimmunoassay showed that beta 2m increased steady state IGF I transcripts and medium IGF I polypeptide levels. These results indicate that the growth-promoting activity of beta 2m is mediated at least in part by regulating local IGF I binding and synthesis by skeletal cells.
Centrella
M
M
Department of Medicine (Endocrine Section), Saint Francis Hospital and Medical Center, Hartford, Connecticut 06105.
McCarthy
T L
TL
Canalis
E
E
D000818:Animals; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004357:Drug Synergism; D004622:Embryo, Mammalian; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D017451:Receptors, Somatomedin; D015291:Transforming Growth Factors / Q000494:pharmacology; D001613:beta 2-Microglobulin / Q000494:pharmacology*
D011956:Receptors, Cell Surface; D017451:Receptors, Somatomedin; D001613:beta 2-Microglobulin; D007334:Insulin-Like Growth Factor I; D015291:Transforming Growth Factors; D004247:DNA