Parathyroid hormone-stimulated resorption in calvaria cultured in serum-free medium is enhanced by the calcium-mobilizing activity of 1,25-dihydroxyvitamin D-3

Citation
W. Li et Mc. Farach-carson, Parathyroid hormone-stimulated resorption in calvaria cultured in serum-free medium is enhanced by the calcium-mobilizing activity of 1,25-dihydroxyvitamin D-3, BONE, 29(3), 2001, pp. 231-235
Citations number
35
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Endocrynology, Metabolism & Nutrition","da verificare
Journal title
BONE
ISSN journal
8756-3282 → ACNP
Volume
29
Issue
3
Year of publication
2001
Pages
231 - 235
Database
ISI
SICI code
8756-3282(200109)29:3<231:PHRICC>2.0.ZU;2-5
Abstract
1,25(OH)(2)D-3 enhances parathyroid hormone (PTH)-induced Ca2+ signaling in osteoblasts by activating plasma membrane voltage-sensitive Ca2+ channels (VSCCs). The ability of 1,25(OH)(2)D-3 or the VSCC-activating analog AT (25 -hydroxy-16-ene-23-yne-D-3) to enhance parathyroid hormone-stimulated Ca-45 (2+) release from cultured new-born rat calvaria was measured. Analog BT (1 ,24-dihydroxy-22-ene-24-cyclopropyl-D-3), that does not mobilize Ca2+, also was tested along with PTH. Control experiments were performed with and wit hout PTH and with and without serum. Individual calvaria labeled in utero w ith Ca-45(2+) were cultivated in serum-free medium on filters at the medium /air interface of 24-well culture plates and Ca-45(2+) release followed ove r 72 h. The results demonstrated that 1,25(OH)(2)D-3 and the Ca2+-mobilizin g analog, AT, but not the nuclear receptor-binding analog, BT, enhanced PTH -stimulated Ca-45(2+) release under serum-free conditions. This enhancement effect of the secosteroids was not evident in the presence of 10% fetal ca lf serum. The effect of analog AT was faster than that of 1,25(OH)(2)D-3. N itrendipine, a specific L-type VSCC blocker, attenuated enhancement by vita min D compounds, indicating that the high-threshold L-type VSCC is a molecu lar transducer of costimulation. These results emphasize the synergy betwee n the calcitropic hormones 1,25(OH)(2)D-3 and PTH in cultures containing os teoblasts and osteoclasts, and suggest that the Ca2+-mobilizing activity of 1,25(OH)(2)D-3 enhances Ca2+ release from bone. (Bone 29:231-235; 2001) (C ) 2001 by Elsevier Science Inc. All rights reserved.