ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
The islated osteoclast bone resorption assay has proved to be a useful means of examining the response of mammalian and avian osteoclasts to a variety of stimuli. The assay has traditionally been performed over a period of 24 hours. By extending the duration of the osteoclast bone resorption assay, we have been able to assess the long-term effects of carboxyl-terminal parathyroid hormone-related protein (hPTHrP[107-139]), salmon calcitonin (sCT) and hPTH[1-34] on bone resorption and TRACP-positive osteoclast-like cell number. We found that, in control cultures over a period of up to 144 hours, the osteoclast-like cells not only remained viable but their numbers also increased. The number of mononucleated and multinucleated osteoclast-like cells doubled in the first 48 hours before stabilizing over the remainder of the incubation period. Osteoblasts also proliferated, resulting in a resorption response to hPTH [1-34] being evident from 48 hours onward. hPTHrP[107-139] persistently inhibited basal and PTH-stimulated bone resorption for at least 96-144 hours. Where as “escape” from the inhibijtory effect of sCT was seen after 48-72 hours. Decreased numbers of bothe mononucleated and multinucleated TRACP-positive osteoclast-like cells were seen by 48 hours in cultures treated with sCT. In contrast, hPTHrP[107-139] reduced the number of mononuclear TRACP-positive cells with only a late effect on multinucleated cells. Furthermore, the incsreased number of osteoclast-like cells seen in response to hPTH[1-34] was inhibited by carboxyl-terminal PTHrP. In summary, this study indicates that the extended bone resorption assay system is a complex one where bothe osteoclastic resorption and osteoclast maturation are evident. Using this syste, we have shown that hPTHrP[107-139] acts as a potent long-term inhibitor of osteoclastic bone resorption, without evidence of escape from its effect. Its action to reduce the number of mononucleated osteoclst-like cells suggests that it affects several aspects of osteoclast activity. © 1993 Wiley-Liss, Inc.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1041550102
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