Production of calcification inhibitors by rat calvaria and bone cells in culture.
Inhibition of calcium phosphate crystal formation was assessed in conditioned medium from cultured rat calvaria and rat calvaria cells. The amount of inhibitor activity was measured by determining the amount of hydroxyapatite needed to induce calcium phosphate precipitation in a solution with a constant calcium phosphate supersaturation. Rat calvaria in culture released inhibitor activity. This activity was separated by chromatography on a Bio-Gel P4 column into a high molecular weight (HMW) fraction and a low molecular weight (LMW) fraction. The latter contained, among others, citrate and pyrophosphate (PPi), but the concentration of these was too low to account for the total activity observed. The identity of the HMW and the remaining LMW inhibitors are at present unknown. Various populations of calvaria cells also produced these two types of inhibitors, 20% of the LMW being due to PPi. Fibroblasts produced only the HMW type of inhibitors. These results suggest that cells might control the process of biologic calcification by regulating the amount of inhibitors they produce.
Ohya
K
K
Department of Pathophysiology, University of Bern, Switzerland.
Meyer
J L
JL
Felix
R
R
Fleisch
H
H
D000818:Animals; D002113:Calcification, Physiologic / Q000187:drug effects; D002130:Calcium Phosphates / Q000096:biosynthesis; D002478:Cells, Cultured; D002850:Chromatography, Gel; D017886:Durapatite; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D006882:Hydroxyapatites / Q000494:pharmacology; D008970:Molecular Weight; D010011:Osteocytes / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012886:Skull
D002130:Calcium Phosphates; D006882:Hydroxyapatites; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; D017886:Durapatite; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous