Influence of parathyroidectomy, 1,25-dihydroxyvitamin D3 and high dietary calcium intake on demineralized bone matrix powder-induced bone formation in the rat.
Demineralized bone matrix induces ectopic endochondral bone formation. We used this model to study the effect of parathyroidectomy (PTX), 1,25-dihydroxyvitamin D3 treatment, and calcium enriched diet on bone formation in the rat. Hypocalcemia and hyperphosphatemia in PTX rats were corrected by 1,25-dihydroxyvitamin D3 treatment (2 x 12.5 ng/day) or by calcium enriched diet (3% calcium). Serum 1,25-dihydroxyvitamin D3 concentration was decreased in PTX rats and in intact rats with high dietary calcium intake. Calcium content of ectopic new bones (42 days after bone matrix implantation) was reduced in PTX rats compared with intact control rats. This could be prevented by 1,25-dihydroxyvitamin D3 treatment. In contrast, calcium enriched diet led to diminished mineralization of ectopic bones both in intact and PTX rats. We conclude that the effect of parathyroidectomy on bone formation may be mediated by 1,25-dihydroxyvitamin D3. 1,25-Dihydroxyvitamin D3 directly stimulates bone formation in this model and this effect is not simply the result of increasing serum calcium concentration.
Lempert
U G
UG
Department of Internal Medicine I, Endocrinology and Metabolism, University of Heidelberg, FRG.
Scharla
S H
SH
Minne
H W
HW
Ziegler
R
R
D000818:Animals; D001857:Bone Matrix / Q000502:physiology*; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood / Q000494:pharmacology*; D002118:Calcium / Q000097:blood; D002136:Calcium, Dietary / Q000494:pharmacology*; D005260:Female; D005269:Femur; D006132:Growth Plate / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D006996:Hypocalcemia; D010012:Osteogenesis / Q000187:drug effects*; D016105:Parathyroidectomy; D010758:Phosphorus / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains
D002136:Calcium, Dietary; D010758:Phosphorus; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium