Osteoclasts are large, irregularly-shaped, multinucleated cells. They are the primary cells responsible for the mobilization of calcium from bone (bone resorption). It is a well known fact that bone diseases (i.e. osteoporosis and osteopetrosis) occur as a result of unbalanced cellular activity. The implicated bone cells include osteoblasts (bone forming cells) and osteoclasts. The earlier one can detect abnormal bone cell function, the more efficient will be the diagnosis and treatment of diseased bone tissue.

Numerous studies have been done on osteoclast morphology and function in vitro (Kallio, et al., 1972; Chambers and Magnus, 1982; Warshafsky, et al., 1985). On the other hand, in vivo studies showing time related early morphologic responses of osteoclasts to calcium repletion have not been done. Weanling Sprague-Dawley rats provide a reliable animal model for in vivo osteoclast research.

We placed weanling Sprague-Dawley rats (72.9 g average weight) on a calcium deficient diet for 7 to 10 days. On the last night of the experiment, the experimental animal group was given a calcium supplemented meal for varying time periods: 30, 90, 180 and 360 minutes. At the end of each given time period, the animals were anesthetized with ether and blood was withdrawn from the animals for calcitonin assay. The animals were perfusion fixed and the diaphyseal portions of both tibias of each animal were decalcified using 3.7% EDTA and embedded in Poly/Bed 812. After sectioning the tissues and staining them with toluidine blue, the sections were qualitatively and quantitatively analyzed with the light microscope. For the quantitative analysis, indices of bone-osteoclast contact were employed.

No significant response of serum calcitonin was observed and therefore it is not known to what extent the osteoclast response was due to the action of calcitonin. Changes in osteoclast morphology and in their relationship to bone may have begun as early as 30 minutes. but significant changes were not observed until three hours after beginning calcium repletion. This indicates that osteoclasts can participate in the physiological responses to postprandial calcium absorption.

LLU Discipline





Graduate School

First Advisor

Paul J. McMillan

Second Advisor

David J. Baylink

Third Advisor

Robert L. Schultz

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Osteoclasts -- cytology; Calcium -- deficiency; Calcitonin -- analysis



Page Count

vi; 83

Digital Format


Digital Publisher

Loma Linda University Libraries

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This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives

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Anatomy Commons