Boland R L, de Boland A R, Nobiling R, Weinreich T, Ritz E
Departamento de Biologia, Universidad Nacional del Sur. Bahia Blanca, Argentina.
Biochem Biophys Res Commun. 1991 Oct 31;180(2):833-40. doi: 10.1016/s0006-291x(05)81140-4.
The acute effects of 1,25-Dihydroxy-vitamin D3 [1,25(OH)2D3] on the concentration of cytoplasmic ionized calcium [Ca2+] of cultured rat mesangial cells were studied at the single cell level by microspectrofluorometry of fura-2-loaded cells. Addition of 1,25(OH)2D3 produced an immediate increase of [Ca2]+. This rise in [Ca2+] was sustained and similar to that caused by the Ca2+ channel agonist BAY K 8644. Comparable changes were also observed in cultured human mesangial cells. The effects of the hormone (10 (-10)-10(-7) M) were dose-dependent (62% and 285%). Only 30-40% of the cells responded to stimulation with 1,25(OH)2D3. 25OHD3 also increased Ca2+ whereas 24,25(OH)2D3 and 1aOHD3 were inactive. Addition of 1 mM CoCl2 or 2-5 microM nifedipine largely blocked the effects of 1,25(OH)2D3 suggesting the involvement of Ca2+ channel activation in the rapid 1,25(OH)2D3-induced increase in mesangial cell [Ca2+]. 45Ca uptake studies are consistent with This interpretation.
采用fura-2负载细胞的显微分光荧光测定法，在单细胞水平研究了1,25-二羟基维生素D3[1,25(OH)2D3]对培养的大鼠系膜细胞胞质游离钙离子[Ca2+]浓度的急性影响。添加1,25(OH)2D3可使[Ca2+]立即升高。[Ca2+]的这种升高持续存在，且与Ca2+通道激动剂BAY K 8644引起的升高相似。在培养的人系膜细胞中也观察到了类似的变化。该激素（10(-10)-10(-7)M）的作用呈剂量依赖性（62%和285%）。只有30%-40%的细胞对1,25(OH)2D3刺激有反应。25OHD3也能增加Ca2+，而24,25(OH)2D3和1aOHD3无活性。添加1 mM CoCl2或2-5 microM硝苯地平可大大阻断1,25(OH)2D3的作用，提示Ca2+通道激活参与了1,25(OH)2D3诱导的系膜细胞[Ca2+]快速升高。45Ca摄取研究与该解释一致。
