PTH & bone resorbing protein effects on chick bone
Date
1986
DOI
Authors
Su, Mingfang
Version
OA Version
Citation
Abstract
A protein, Bone Resorbing Protein (BRP),isolated from human cancer ascites fluid, which has the ability to influence the metabolism of bone, was examined and compared with human 1-34 amino terminal fragment of parathyroid hormone (PTH) on bone calcium mobilization, matrix resorption, and collagen synthesis. Interactions of PTH and BRP on these areas of bone metabolism were also examined. Embryonic chick calvaria were chosen as an assay system because it is not primarily a resorbing system and permits measurement of all three areas of bone metabolism under identical conditions.
Using this type of assay system we have shown that both PTH and BRP are capable of stimulating bone resorption. In addition, both of these agents induced significant stimulation of proline incorporation and conversion to hydroxyproline. In contrast to their similar action on calcium mobilization and proline incorporation, PTH but not BRP was effective in stimulating matrix resorption. We found that a dosage as low as 25 ug/ml of BRP has slight but significant stimulatory effects on bone calcium mobilization and inhibitory effects on matrix resorption. A level of 333 ug/ml of BRP gave a maximum response for bone calcium mobilization. These bone resorption response can be detected as early as 24 hours after exposure. We also found that BRP and PTH have co-operative activity on calcium mobilization and antagonistic effects on matrix resorption. Calcitonin, an inhibitor of calcium mobilization, had antagonistic effects on proline incorporation with PTH but co-operative effects with BRP. In the induction of bone resorption, our data show that 2 hours exposure to BRP has the same significant activity on bone resorption as 72 hours exposure. These effects may have significance in explaining the mechanisms involved in producing humoral hypercalcemia of malignancy.
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Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1986 (Oral Biology)
Bibliography : leaves 72-84.
Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1986 (Oral Biology)
Bibliography : leaves 72-84.
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This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.