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Skeletal alterations in hypophysectomized rats: I. A histomorphometric study on tibial cancellous bone
1Department of Medicine, Winthrop-University Hospital, Mineola, New York, USA.
The Anatomical Record
|April 1, 1995
Summary
Hypophysectomy (HX) in rats halts bone growth and reduces bone metabolism. This study shows HX causes cancellous bone loss primarily by suppressing growth and inhibiting tissue-based bone turnover.
Area of Science:
- Endocrinology
- Bone Biology
- Skeletal Physiology
Background:
- Hypophysectomy (HX) leads to cessation of bone growth and decreased bone metabolism.
- Pituitary hormone deficiency significantly impacts skeletal development and maintenance.
Purpose of the Study:
- To investigate the effects of hypophysectomy (HX) on static and dynamic histomorphometry of cancellous bone.
- To analyze changes in the secondary spongiosa of the proximal tibial metaphysis in rats following HX.
Main Methods:
- Female rats underwent HX and were sacrificed at various time points (0, 5 days, 2, 5 weeks).
- Age-matched intact rats served as controls.
- Cancellous bone histomorphometry and tartrate-resistant acid phosphatase staining were performed on tibial sections.
Main Results:
- HX rats showed no increase in body weight, tibial length, or density compared to controls.
- Cancellous bone volume and trabecular number decreased, while separation increased in HX rats.
- HX significantly reduced longitudinal growth rate and tissue-based bone formation and resorption, but not surface-based turnover.
Conclusions:
- Pituitary hormone deficiency causes cancellous bone loss in rats.
- Bone loss is attributed to suppressed growth-dependent bone gain and inhibited tissue-based bone turnover.
- Surface-based bone turnover remains unaffected by HX.