LOCAL-ACTION OF PHOSPHATE-DEPLETION AND INSULIN-LIKE GROWTH-FACTOR-1 ON IN-VITRO PRODUCTION OF 1,25-DIHYDROXYVITAMIN-D BY CULTURED MAMMALIAN KIDNEY-CELLS
LOCAL-ACTION OF PHOSPHATE-DEPLETION AND INSULIN-LIKE GROWTH-FACTOR-1 ON IN-VITRO PRODUCTION OF 1,25-DIHYDROXYVITAMIN-D BY CULTURED MAMMALIAN KIDNEY-CELLS
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DOI：
10.1172/jci117512
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发表时间：
1994-10-01
影响因子：
15.9
通讯作者：
GARABEDIAN, M
中科院分区：
文献类型：
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作者：
CONDAMINE, L;VZTOVSNIK, F;GARABEDIAN, M
激素形式的维生素D，1，25（OH）（2）D，主要在近端肾小管细胞中合成。实验和临床研究表明，生长激素可能参与了与生长相关的血浆1，25（OH）（2）D的波动和体内缺磷诱导的1，25（OH）（2）D的增加，这种作用可能由胰岛素样生长因子1（IGF 1）介导。我们测试了磷酸盐消耗和IGF 1添加对培养的肾细胞中1，25（OH）（2）D-3产生的影响：负鼠肾（OK）细胞、LLC-PK 1和兔近端肾小管细胞。在存在和不存在IGF 1的情况下，将汇合的细胞单层在各种磷酸盐浓度下预孵育，然后，向培养基中加入5 nM [H-3]25（OH）D-3或2 μ M 25（OH）D-3，并将细胞再孵育120 min。在两种不同的直相高效液相色谱法后测定脂质提取物中生物合成的1，25（OH）（2）D-3的量。实验结果表明：（a）LLC-PK 1和兔细胞表达可检测的合成1，25（OH）（2）D-3的能力，而OK细胞不表达。(b)部分或全部磷酸盐剥夺分别增加LLC-PK 1和兔细胞中1，25（OH）（2）D-3的产生量。(c)IGF 1（25 ng/ml）可增加兔细胞中1，25（OH）（2）D-3的产生，特别是在无磷酸盐培养基中（1.6倍），以及在部分磷酸盐耗竭的LLC-PK 1细胞中（1 mM磷酸盐中为2.75倍，P = 0.015，n = 5，0.5mM磷酸盐中为3.2倍，P = 0.043，n = 4）。我们的研究结果表明磷酸盐消耗和IGF 1对1，25-二羟维生素D-3产生的局部作用
The hormonal form of vitamin D, 1,25(OH)(2)D, is synthesized mostly in proximal renal tubular cells. Experimental and clinical studies suggest that the growth hormone may be involved in growth-related fluctuations of plasma 1,25(OH)(2)D and in the increase of 1,25(OH)(2)D induced by in vivo phosphate deprivation, an action possibly mediated by insulin-like growth factor 1 (IGF 1). We tested the effects of phosphate depletion and IGF 1 addition on 1,25(OH)(2)D-3 production in cultured kidney cells: opossum kidney (OK) cells, LLC-PK 1, and rabbit's proximal tubular cells.Confluent cell monolayers were preincubated in various phosphate concentrations, in the presence and absence of IGF 1, Then, 5 nM of [H-3]25(OH)D-3 or 2 mu M of 25(OH)D-3 were added to the medium and the cells were incubated for a further 120 min. The amount of biosynthesized 1,25(OH)(2)D-3 in lipid extracts was determined after two different straight phase high performance liquid chromatographies. The experiment showed the following: (a) LLC-PK 1 and rabbit's cells expressed a detectable ability to synthesize 1,25(OH)(2)D-3, while OK cells did not. (b) Partial or total phosphate deprivation increased the amount of 1,25(OH)(2)D-3 produced, respectively in LLC-PK 1 and in rabbit's cells. (c) IGF 1 (25 ng/ml) increased 1,25(OH)(2)D-3 production in rabbit's cells, particularly in phosphate-free medium (1.6-fold), and in LLC-PK 1 cells, in partial phosphate depletion (2.75-fold in 1 mM phosphate, P = 0.015, n = 5, and 3.2-fold in 0.5 mM phosphate, P = 0.043, n = 4). Our findings demonstrate a local action of phosphate depletion and of IGF 1 on 1,25-dihydroxyvitamin D-3 production