Abstract.
The C-terminal (107-111) region of parathyroid hormone-related protein (PTHrP) appears to inhibit osteoclastic bone resorption, and to affect osteoblastic growth and differentiation. We tested the effect of human PTHrP (107-139) on alkaline phosphatase (ALP) activity in osteoblastic osteosarcoma UMR 106 cells. We found that this C-terminal PTHrP peptide, between 10 nM and 10 fM, inhibited ALP activity in these cells during the log phase of growth. Human PTHrP (1-34) amide and human PTHrP (1-141) were as potent as PTHrP (107-139) in growing UMR 106 cells. This inhibitory effect of 10 nM PTHrP (107-139) on ALP activity was also observed in serum-depleted cells, and in the presence of 10 nM dexamethasone, which increased ALP activity by 40% in these cells. In addition, this effect of PTHrP (107-139) was blunted by 25 nM bisindolylmaleimide I, a protein kinase C inhibitor. These results support a role for the C-terminal region of PTHrP as a modulator of bone formation.
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Received: 7 July 1998 / Accepted: 10 January 1999
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Valín, A., de Miguel, F., García-Ocaña, A. et al. Parathyroid Hormone-Related Protein (107-139) Decreases Alkaline Phosphatase in Osteoblastic Osteosarcoma Cells UMR 106 by a Protein Kinase C-Dependent Pathway. Calcif Tissue Int 65, 148–151 (1999). https://doi.org/10.1007/s002239900674
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DOI: https://doi.org/10.1007/s002239900674