Bone mineralization and metabolism of 3H-25-hydroxyvitamin D3 in thyroparathyroidectomized rats treated with parathyroid extract.
Thyroparathyroidectomized rats fed a diet containing 1.2% calcium, 0.55% phosphorus maintain normal serum levels of these ions. Treatment of such rats with parathyroid extract (PTE; 20 U/100 g twice daily; 10 days) has no statistically significant effect on rates of bone formation, matrix apposition, or osteoid maturation. Significant decreases in osteoid width and mineralizing front width, as well as a 60% increase in the rate of initial mineralization were observed in the PTE-treated group. Conversion of 3H-25-hydroxyvitamin D3 to 3H-1,25-dihydroxyvitamin D3 was 4-fold higher in the PTE-treated group than in the untreated animals. Increased formation of 1,25-dihydroxyvitamin D3 in response to treatment with PTE may play a major role in correcting the mineralizing defect resulting from thyroparathyroidectomy.
D000818:Animals; D001857:Bone Matrix / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D002118:Calcium / Q000097:blood; D006887:Hydroxycholecalciferols / Q000378:metabolism*; D008297:Male; D008903:Minerals / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D010280:Parathyroid Glands / Q000502:physiology* / Q000601:surgery; D010758:Phosphorus / Q000097:blood; D051381:Rats; D013965:Thyroidectomy; D014020:Tissue Extracts / Q000494:pharmacology*
D006887:Hydroxycholecalciferols; D008903:Minerals; D014020:Tissue Extracts; D010758:Phosphorus; D002118:Calcium