Effect of (Asu1,7)-eel calcitonin on the prevention of osteoporosis induced by combination of immobilization and ovariectomy in the rat.
Experimental osteoporosis was induced in the rat by a combination of ovariectomy and immobilization by hemicordotomy. (Asu1,7)-eel calcitonin (CT) was administered at doses of 0.1, 0.5, 1.0, 2.5, and 5.0 MRC unit/kg, and its preventive effect on bone loss was examined. Significant bone loss was observed in the untreated control group by photo-densitometry and measurement of bone mass. CT at doses of above 1.0 MRC unit/kg significantly increased femur scores and at doses of above 2.5 MRC unit/kg resulted in significantly higher photodensity. Dry weight and ash weight were significantly higher in the 2.5 and 5.0 MRC unit/kg CT-treated groups. Administration of CT had a nearly dose-dependent effect on bone mass. Histomorphometry revealed significantly lower fractional formation surface and fractional resorption surface in the 5.0 MRC unit/kg CT-treated group. Bone mineralization was studied by the quantitative analysis of tetracycline incorporation. Tetracycline uptake was significantly lower in the groups treated with CT at doses above 1.0 MRC unit/kg. The kinetic bone formation activity studied by 45Ca and 14C-proline tracer examination, in the 5.0 MRC unit/kg CT-treated group was significantly lower than that in the control group, but not lower than that in the sham-operated group.
Hayashi
T
T
Department of Orthopaedic Surgery, Faculty of Medicine, Kyoto University, Japan.
Yamamuro
T
T
Okumura
H
H
Kasai
R
R
Tada
K
K
D000818:Animals; D001842:Bone and Bones / Q000187:drug effects; D002116:Calcitonin / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D003720:Densitometry; D004305:Dose-Response Relationship, Drug; D005260:Female; D007103:Immobilization; D010012:Osteogenesis / Q000187:drug effects; D010024:Osteoporosis / Q000209:etiology / Q000517:prevention & control*; D010052:Ovariectomy; D051381:Rats; D011919:Rats, Inbred Strains; D013752:Tetracycline
D002116:Calcitonin; D013752:Tetracycline; C012755:elcatonin