Effect of 1,25-dihydroxyvitamin D3 on phosphate homeostasis in the X-linked hypophosphatemic (Hyp) mouse.
Effect of 1,25-dihydroxyvitamin D3 on phosphate homeostasis in the X-linked hypophosphatemic (Hyp) mouse.
复制标题
1,25-二羟基维生素 D3 对 X 连锁低磷血症 (Hyp) 小鼠磷酸盐稳态的影响。
作者：
H. Tenenhouse;C. Scriver
我们研究了1，25-二羟维生素D3对1，25-（OH）_2D_3对小鼠低磷血症（Hyp）中无机磷（Pi）稳态的影响，Hyp是人类X连锁低磷血症（XLH）的同源物。（83 pg/g.d，连续亚切，输注x10 d）的血浆钙（Ca）水平显著升高（p <0.001），血浆Pi（p <0.025）和Ca排泄分数（p <0.001），而纯化的肾刷状缘膜囊泡（BBMV）中Pi排泄分数或Na+刺激的Pi转运无变化。Hyp同窝仔对该剂量的1，25-（OH）2D 3没有反应。在415 pg/g.d时，Hyp小鼠血浆Ca（p <0.001）、Ca排泄分数（p <0.001）和血浆Pi（p <0.001）增加，但BBMV中Pi排泄分数或Na+刺激的Pi转运均无变化。在该剂量下，1，25-（OH）2D 3也刺激了Hyp小肠外翻囊的Pi转运（p小于0.001）。未处理的Hyp肠中未发现Pi转运的缺陷。我们的结论是，1，25-（OH）2D 3通过其对肠道的影响改善了Hyp表型中的Pi稳态;肾脏Pi重吸收的缺陷保持不变。
We studied the effect of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on homeostasis of inorganic phosphate (Pi) in murine hypophosphatemia (Hyp), a homologue of X-linked hypophosphatemia (XLH) in man. Normal mice given 1,25-(OH)2D3 (83 pg/g.d) by continuous subcut, infusion x 10 d) had a significant rise in plasma calcium (Ca) (p less than 0.001), plasma Pi (p less than 0.025) and fractional Ca excretion (p less than 0.001), without change in fractional Pi excretion or Na+-stimulated Pi transport in purified renal brush-border membrane vesicles (BBMV). Hyp littermates did not respond to this dose of 1,25-(OH)2D3. At 415 pg/g.d, Hyp mice had increased plasma Ca (p less than 0.001), fractional Ca excretion (p less than 0.001), and plasma Pi (p less than 0.001) but no change in either fractional Pi excretion or Na+-stimulated Pi transport in BBMV. At this dose, 1,25-(OH)2D3 also stimulated Pi transport by everted sacs of Hyp small intestine (p less than 0.001). No deficiency of Pi transport was found in untreated Hyp intestine. We conclude that 1,25-(OH)2D3 improves Pi homeostasis in the Hyp phenotype by its effect on intestine; the defect in renal Pi reabsorption remains unchanged.