1α,25-dihydroxyvitamin D3 acts predominately in mature osteoblasts under conditions of high extracellular phosphate to increase fibroblast growth factor 23 production in vitro
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Yoshioka, Hirotaka 大学院医歯薬保健学研究院（歯）
Aubin, Jane E
Osteoblasts/osteocytes are the principle sources of fibroblast growth factor 23 (FGF23), a phosphaturic hormone, but the regulation of FGF23 expression during osteoblast development remains uncertain. Because 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) and inorganic phosphate (Pi) may act as potent activators of FGF23 expression, we estimated how these molecules regulate FGF23 expression during rat osteoblast development in vitro. 1,25(OH)2D3-dependent FGF23 production was restricted largely to mature cells in correlation with increased vitamin D receptor (VDR) mRNA levels, in particular, when Pi was present. Pi alone and more so in combination with 1,25(OH)2D3 increased FGF23 production and VDR mRNA expression. Parathyroid hormone, stanniocalcin 1, prostaglandin E2, FGF2, and foscarnet did not increase FGF23 mRNA expression. Thus, these results suggest that 1,25(OH)2D3 may exert its largest effect on FGF23 expression/production when exposed to high levels of extracellular Pi in osteoblasts/osteocytes.
This work was supported in part by grants from the Ministry of Education, Science, Sports and Culture of Japan (18592001 to YY) and the Canadian Institutes of Health Research (FRN 83704 to JEA).
Journal of Endocrinology
Society for Endocrinology
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