Adult human osteoblast-like cells do not express insulin-like growth factor-I.
Previous studies using cultures of fetal rodents calvaria have indicated an important role for insulin-like growth factor-I (IGF-I) in the local control of bone formation. In this study, we have examined the expression of IGF-I in adult human osteoblast-like (hOB) cells. To detect very low levels and to distinguish between the two IGF-I mRNA transcripts Ea and Eb, which are formed by alternate splicing, we have used the reverse transcriptase-polymerase chain reaction (RT-PCR). Expression of both Ea and Eb IGF-I mRNA transcripts were found in human liver and in placenta. However, neither Ea nor Eb IGF-I mRNA could be detected under basal conditions or after stimulation with growth hormone in normal hOB cells and two human osteosarcoma cell lines with osteoblastic properties, SaOS-2 and MG-63. We conclude that adult hOB cells do not synthesize IGF-I. Thus, in contrast to its crucial role as a local regulator of skeletal remodeling in fetal rodent bone, IGF-I does not appear to have this autocrine function in adult human bone.
Ström
P
P
Department of Internal Medicine, University Hospital, Uppsala, Sweden.
Ljunghall
S
S
Melhus
H
H
D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D015870:Gene Expression; D006801:Humans; D066298:In Vitro Techniques; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008099:Liver / Q000502:physiology; D008969:Molecular Sequence Data; D010006:Osteoblasts / Q000502:physiology*; D012516:Osteosarcoma; D010920:Placenta / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I