The effect of PTH on prostaglandin synthesis in chick calvaria and cells
Date
1986
DOI
Authors
Yang, Chin-Yuh
Version
OA Version
Citation
Abstract
Synthetic human parathyroid hormone N-terminal 1-34 peptide (hPTH 1-34) stimulates calcium mobilization in chick calvaria. The release of [45]Ca from pre-labeled embryonic chick calvaria was increased significantly after 48 h of exposure to hPTH 1l-34. This effect persisted for at least 12O h in culture. Indomethacin, at a concentration of 10[-5] M, had a slight inhibitory effect on hPTH 1-34 mediated bone resorption. Exogenous PGE[2] also showed slight stimulatory effects on calcium mobilization in chick calvaria, although its effects were far less than the effects of hPTH 1-34. Human PTH 1-34 significantly stimulates DNA synthesis in intact bones and the nonperiosteal portion of the bones.
Human PTH 1-34 stimulates PG production by chick calvaria in culture. PGE[2] was the predominant PG found by both RIA and HPLC. Stimulation of PGE[2] synthesis was significant at 50 ng/ml (1.2 x 10[8] M) of hPTH 1-34 and was dose dependent at concentrations up to 0.6 ug/ml (1.4 x 1O[M]). Continuous exposure of calvaria to hPTH 1-34 showed that PGE[2] production increased significantly by 1h, reached a maximum at 4 h and then persisted over 96 h. Indomethacin, at concentrations above 5x10[-7]M, inhibited PGE[2] synthesis by both control and hPTH 1-34 treated bones. Human PTH 1-34 stimulated bone cells to convert arachidonic acid to PGE[2], but did not activate the bone to release stored arachidonate. In summary, our results suggest synthesis calvaria.
Two cell populations, designated as PF and OB cells, were isolated from chick calvaria by centrifugation on a Percoll gradient. In culture, the PF cells are large and spindle-shaped while the OB cells appear as small, polygonal-shaped cells. Both cell populations required heat-inactivated fetal calf serum (HI-FCS) for attachment and proliferation. The PF cells proliferated faster than OB cells in 10% HI-FCS. Both PF and OB cells synthesized predominantly PGD subscript 2. PGE[2] was the second major PG product and the OB cells produced a little more PGE[2] than PF cells. PG production increased significantly when PF and OB cells were mixed at a 1 : 1 ratio. Human PTH 1-34 and EGF showed no stimulatory effect on PGD subscript 2 synthesis in either of these cell populations, although the two hormones stimulated PCE subscript 2 synthesis in OB cells. Indomethacin, at a concentration of 5 x 10[-6] M, blocked PG synthesis by OB cells. The differences between the intact bone and the cells isolated from the same bone in terms of PG production is uncertain at this time. The mechanism involved in these differences may represent a very important physiologic modification both in vivo and in vitro.
Description
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Black and white photographs included.
Thesis (D.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1986 (Oral Biology)
Bibliography : leaves 173-193.
Black and white photographs included.
Thesis (D.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1986 (Oral Biology)
Bibliography : leaves 173-193.
License
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.