[Effects of 1,25 dihydroxyvitamin d3 on the morphology and alkaline phosphatase activity of ROS 17/2,8 osteoblastic cells: influence of time and dose].
Osteosarcoma-derived osteoblastic cells were exposed to 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) either to 0.001-1,000 nmol.l-1 for 4 days or to 10 nmol.-1 for 1-21 days. Between 0.01 and 10 nmol.l-1, a dose-dependent increase in alkaline phosphatase (AP) activity was found, which rose to a maximum level at 10 nmol.l-1 (+55%). At higher doses (100 and 1,000 nmol.l-1), 1,25(OH)2D3 induced a decrease in AP activity of 40%. After 1 day at 10 nmol.l-1 a slight increase in AP activity was noted (+20%) which augmented with the duration of exposure. This stimulatory effect was highest after 8 days (+130%). In contrast, after 15 and 21 days, AP activity decreased by 30%. Under 1,25(OH)2D3, microtubules were observed mainly in the perinuclear region.
Faculté Alexis Carrel, INSERM Unité 234, Lyon, France.
P
P
Chavassieux
G
G
Boivin
C
C
Terrier
C M
CM
Serre
D
D
Lagarde
P J
PJ
Meunier
D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D002117:Calcitriol / Q000008:administration & dosage / Q000494:pharmacology*; D002467:Cell Nucleus / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D008854:Microscopy, Electron; D008870:Microtubules / Q000648:ultrastructure; D010006:Osteoblasts / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure*; D012516:Osteosarcoma; D051381:Rats; D014407:Tumor Cells, Cultured
D000469:Alkaline Phosphatase; D002117:Calcitriol
Effets de la 1,25 dihydroxyvitamine D3 sur la morphologie et l'activité phosphatase alcaline des cellules ostéoblastiques ROS 17/2,8: influence du temps et de la dose.