Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Genetic Phenomena
Glucocorticoid Regulation Of Insulin Like Growth Factor Binding Protein-5 Gene Transcription In Human Osteoblasts, Xiaoying Wang
Glucocorticoid Regulation Of Insulin Like Growth Factor Binding Protein-5 Gene Transcription In Human Osteoblasts, Xiaoying Wang
Loma Linda University Electronic Theses, Dissertations & Projects
Glucocorticoids (GCs) inhibit bone formation in vivo and inhibit osteoblast proliferation and collagen synthesis in vitro. These effects may be mediated by alterations in the insulin-like growth factor (IGF) system. In the present study of normal human osteoblast-like (HOB) cells, we tested the hypothesis that dexamethasone (Dex) inhibits the expression of IGF binding protein-5 (IGFBP-5). Dex decreased IGFBP-5 mRNA levels to 54% of control after 4 hr. Dex did not modify the decay of IGFBP-5 mRNA in transcriptionally arrested osteoblast cells. Dex decreased IGFBP-5 hnRNA levels to 67% of control after 2 hr, and the activity of the human IGFBP- …
Molecular Mechanism Of The Stimulation Of Alkaline Phosphatase Activity In Human Bone Cells By 1,25(Oh)2 D3, Eru Kyeyune-Nyombi
Molecular Mechanism Of The Stimulation Of Alkaline Phosphatase Activity In Human Bone Cells By 1,25(Oh)2 D3, Eru Kyeyune-Nyombi
Loma Linda University Electronic Theses, Dissertations & Projects
To facilitate this study an in vitro human model system was established that exhibited many aspects of normal osteoblasts. The human osteosarcoma cell line (TE85 cells) expressed a skeletal alkaline phosphatase activity (an accepted bone cell differentiation marker) which was stimulated by 1,25(OH)2D3 (a potent differentiating agent), under serum-free conditions in a dose-dependent, time-dependent, and cell density-dependent manner. Cytochemical analysis of the stimulation of ALP activity by 1,25(OH)2D3 showed that 1,25(OH)2D3 increased the number of TE85 cells that expressed detectable ALP activity, suggesting that 1,25(OH)2D3 promoted the process …