A direct effect of 24,25-(OH)2D3 and 1,25-(OH)2D3 on the modeling of fetal mice long bones in vitro.
To examine the effects of 24,25-(OH)2D3 and 1,25-(OH)2D3 on fetal long bone modeling the radii and ulnae of 16 day fetal mice were grown in vitro for 2 days. Their growth, mineralization, and resorption were assessed by measuring diaphyseal length, calcium and phosphorus content, hydroxyproline-protein ratios, and the release of incorporated 45Ca. The results showed that 24,25-(OH)2D3 at concentrations of 10(-10)-10(-8) M stimulated the growth of the bones as indicated by their increased diaphyseal length, periosteal bone area, and hydroxyproline content. Calcium and phosphorus content was significantly increased; 45Ca release was unaltered. Bones incubated in media containing 10(-6) M 24,25-(OH)2D3 responded in a similar fashion to bones incubated in media containing 10(-10)-10(-8) M 1,25-(OH)2D3, with inhibition of bone growth as indicated by reduced diaphyseal length, periosteal bone area, hydroxyproline-protein ratios, and calcium and phosphorus content; 45Ca release was significantly increased. Neither metabolite affected total bone length. The results suggest a role for 24,25-(OH)2D3 in the growth of fetal mice bones in vitro and also confirm the findings from previous studies that 1,25-(OH)2D3 and high concentrations of 24,25-(OH)2D2 stimulate bone resorption.
Schwartz
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Z
Department of Periodontics, Hebrew University Hadassah, Faculty of Dental Medicine, Jerusalem, Israel.
Soskolne
W A
WA
Atkin
I
I
Goldstein
M
M
Ornoy
A
A
D015650:24,25-Dihydroxyvitamin D 3; D000818:Animals; D001853:Bone Marrow; D001842:Bone and Bones / Q000187:drug effects* / Q000196:embryology; D002117:Calcitriol / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002356:Cartilage / Q000187:drug effects; D002452:Cell Count; D004100:Dihydroxycholecalciferols / Q000494:pharmacology*; D006909:Hydroxyproline / Q000378:metabolism; D051379:Mice; D009924:Organ Culture Techniques; D010010:Osteoclasts; D010758:Phosphorus / Q000378:metabolism
D004100:Dihydroxycholecalciferols; D010758:Phosphorus; D015650:24,25-Dihydroxyvitamin D 3; D002117:Calcitriol; D006909:Hydroxyproline; D002118:Calcium