Calcium-Transport in Quiescent and 1,25-Dihydroxycholecalciferol-Stimulated Human Osteosarcoma Cells. Role in 24 Hydroxylase Enhancement

C. Rebut-Bonneton; S. Y. Ly; L. Cancela

doi:10.1055/s-2007-1010831

Hormone and Metabolic Research, Inhaltsverzeichnis

Horm Metab Res 1988; 20(6): 339-343
DOI: 10.1055/s-2007-1010831

ORIGINALS

Calcium-Transport in Quiescent and 1,25-Dihydroxycholecalciferol-Stimulated Human Osteosarcoma Cells. Role in 24 Hydroxylase Enhancement

C. Rebut-Bonneton, S. Y. Ly, L. Cancela

INSERM, Paris, France

Abstract

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Summary

The present study evaluates in osteosarcoma cells, the effects of a calcium channel inhibitor nicardipine in 24-hydroxylase activity and ⁴⁵Ca desaturation curve in presence of 1,25-dihydroxycholecalciferol (1,25(OH)₂D₃). This sterol induced an increase in 24-OHase activity and ⁴⁵Ca fluxes. Nicardipine reversed the effect of 1,25(OH)₂D₃ on ⁴⁵Ca fluxes but reinforced the enhancement of the 24-OHase activity. The fact that the effects of 1,25(OH)₂D₃ were reduced by cycloheximide support the hypothesis of a de novo protein synthesis. Our study has allowed us to dissociate the effects of 1,25(OH)₂D₃ on 24-OHase enhancement from those on Ca²⁺ transport.

Key-Words

⁴⁵Ca Kinetics - 1,25-Dihydroxycholecalciferol Osteosarcoma Cells - 24-OHase

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