Identification and characterization of the insulin-like growth factor I receptor in mature rabbit osteoclasts
Identification and characterization of the insulin-like growth factor I receptor in mature rabbit osteoclasts
复制标题
DOI：
10.1359/jbmr.1997.12.4.534
复制
发表时间：
1997-04-01
影响因子：
6.2
通讯作者：
Foged, NT
中科院分区：
文献类型：
--
作者：
Hou, P;Sato, T;Foged, NT
In this study, the insulin-like growth factor I (IGF-I) receptor was identified in rabbit osteoclasts at mRNA and protein levels by in situ hybridization and autoradiography, respectively, Using highly purified mature osteoclasts, the IGF-I receptor was characterized on the molecular level according to its size and its affinity and number per osteoclast by isolation of the receptor-ligand complex and by binding studies, respectively, and on the cellular level according to the response of mature osteoclasts to IGF-I stimulation. In situ hybridization and autoradiography experiments showed that osteoclasts express IGF-I receptor mRNA and IGF-I binding sites, Chemical crosslinking of I-125-IGF-I bound to the purified mature osteoclasts and subsequent sodium dodecyl sulfide-polyacrylamide gel electrophoresis revealed the specific binding of I-125-IGF-I in complexes with molecular masses of 130 and 230 kD consistent with binding to the IGF-I receptor, In competition experiments, I-125-IGF-I binding to mature osteoclasts was dose-dependently reduced by unlabeled IGF-I in the picomolar range,,whereas 20 nM insulin did not reduce the binding of I-125-IGF-I binding, The calculated receptor number was 6000 per osteoclast, and the K-d was 0.10 nM, Searching for a role of the IGF-I receptor in mature osteoclasts, we found no significant influence of IGF-I on the levels of the preform of matrix metaloproteinase 9 and tartrate-resistant acid phosphatase, However, the induction of nuclear fragmentation in serum-depleted cultures of purified mature osteoclasts was dose-dependently inhibited by IGF-I in the picomolar range, but not by 1 nM insulin, These data show that functionally active IGF-I receptor is present in mature osteoclasts.
