Bone specific binding sites for 1,25(OH)2D3 in magnesium deficiency

• Autores: M.L. Traba, F. Risco
• Localización: Journal of physiology and biochemistry, ISSN-e 1877-8755, ISSN 1138-7548, Vol. 60, Nº. 3, 2004, págs. 199-203
• Idioma: inglés
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• Resumen

  • It has been reported that some hypoparathyroid patients with magnesium deficiency showed altered responses to vitamin D treatment. In the same way, in vitro bone studies have demonstrated the existence of a decrease in the 1,25-dihydroxyvitamin D3-induced resorption in bone as a result of magnesium deficiency. These findings suggest some kind of alteration in the 1,25(OH)2D3 in bone in magnesium deficiency. In the present work, using a binding assay based on the 1,25(OH)2D3 and 3H-1,25(OH)2D3 competition for the hormone binding sites in rat calvaria homogenates, a significant decrease in the number of 1,25(OH)2D3 specific binding sites has been found in calvaria incubated in magnesium-deficient medium compared to magnesium-replete ones. Alterations in the hormone-receptor affinity were not found. These results suggest that an alteration in the 1,25(OH)2D3 action on magnesium-deficient bone could be due, at least in part, to a decrease in the number of available vitamin D receptors in bone cells