Complex shape changes in isolated rat osteoclasts: Involvement of protein kinase C in the response to calcitonin

Holloway, W.R., Collier, F.M., Herbst, R.E., Hodge, J.M. and Nicholson, G.C. (1997) Complex shape changes in isolated rat osteoclasts: Involvement of protein kinase C in the response to calcitonin. Calcified Tissue International, 61 4: 306-312. doi:10.1007/s002239900340


Author Holloway, W.R.
Collier, F.M.
Herbst, R.E.
Hodge, J.M.
Nicholson, G.C.
Title Complex shape changes in isolated rat osteoclasts: Involvement of protein kinase C in the response to calcitonin
Journal name Calcified Tissue International   Check publisher's open access policy
ISSN 0171-967X
1432-0827
Publication date 1997-10
Sub-type Article (original research)
DOI 10.1007/s002239900340
Volume 61
Issue 4
Start page 306
End page 312
Total pages 7
Place of publication New York, NY, United States
Publisher Springer
Language eng
Formatted abstract
The cytoplasmic spreading of osteoclasts has been used to assess responsiveness to agents such as calcitonin and associated signal transduction mechanisms. Although cyclic AMP and intracellular calcium are known mediators of calcitonin effects in osteoclasts, the role of protein kinase C (PKC) is less clear. We have used time-lapse videomicroscopy of isolated rat osteoclasts to characterize shape changes induced by calcitonin, forskolin, and phorbol 12-myristate-13-acetate (PMA) in the absence and presence of PKC blockers. Treatment with calcitonin reduced cytoplasmic plan area but increased perimeter length, resulting in a characteristic 'stellate' appearance, whereas forskolin produced 'nonstellate' contraction. The response of osteoclasts to PMA was dose dependent. High concentrations (10 - 7-10 -6 M) produced biphasic responses with transitory, calcitonin-like 'stellate' contraction followed by sustained expansion, whereas low concentrations (10 -11- 10 -9 M) produced expansion only. The effects of low concentration PMA could be prevented by pretreatment with a PKC blocker, whereas the effects of high concentrations were only partially inhibited. The effects of forskolin were unchanged by pretreatment with the PKC blocker. Treatment with calcitonin in the presence of various PKC blockers resulted in paradoxical transient expansion followed by contraction. These results indicate that calcitonin-induced shape change in osteoclasts is a complex process involving protein kinase C in addition to cyclic AMP-dependent mechanisms and possibly other factors.
Keyword Osteoclast
Calcitonin
Protein-kinase-C
Phorbol-ester
Forskolin
Signal transduction
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Medicine Publications
 
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