1 Alpha,25-dihydroxyvitamin D3 rapidly increases cytosolic calcium in clonal rat osteosarcoma cells lacking the vitamin D receptor.
J Bone Miner Res
; 6(12): 1269-75, 1991 Dec.
Article
em En
| MEDLINE
| ID: mdl-1665280
ABSTRACT
1 alpha,25-Dihydroxyvitamin D3 [1 alpha,25-(OH)2D3] rapidly increases cytosolic calcium in a variety of cell types. Although these rapid effects do not appear to directly involve genome activation, the requirement for the classic vitamin D receptor is unclear. Clonal rat osteosarcoma cells, ROS 17/2.8, respond to 1 alpha,25-(OH)2D3 with an increase in osteocalcin message but ROS 24/1 cells do not. The lack of the receptor for vitamin D in the ROS 24/1 cells has been confirmed by the absence of any detectable vitamin D-receptor complex binding to the vitamin D-responsive element (VDRE) of the osteocalcin gene and the absence of vitamin D receptor mRNA in the cells. Quin-2-loaded ROS 17/2.8 and ROS 24/1 cells were treated with 1 alpha,25-(OH)2D3 in the presence and absence of extracellular calcium and with the inactive epimer, 1 beta,25-dihydroxyvitamin D3 [1 beta,25-(OH)2D3]. The 1 alpha,25-(OH)2D3 increased cytosolic calcium in the ROS 17/2.8 and 24/1 cells after 5 minutes in a dose-responsive manner and in the presence and absence of extracellular calcium. Pretreatment of both cell lines with 1 beta,25-(OH)2D3 for 30 s blocked the hormone-induced rise in cytosolic calcium. The rapid effects of 1 alpha,25-(OH)2D3 on ROS cells with and without the vitamin D receptor and the ability of the inactive epimer to inhibit these effects indicate that the signaling system mediating the hormone's rapid actions is not the classic vitamin D receptor.
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Base de dados:
MEDLINE
Assunto principal:
Calcitriol
/
Receptores de Esteroides
/
Osteossarcoma
/
Cálcio
/
Citosol
Limite:
Animals
Idioma:
En
Revista:
J Bone Miner Res
Assunto da revista:
METABOLISMO
/
ORTOPEDIA
Ano de publicação:
1991
Tipo de documento:
Article