Bruns M E, Wallshein V, Bruns D E
Am J Physiol. 1982 Jan;242(1):E47-52. doi: 10.1152/ajpendo.1982.242.1.E47.
To study the developmental controls for both intestinal and placental calcium-binding protein (CaBP), we have altered mineral metabolism by feeding pregnant mice diets high in calcium and strontium. The effects of these dietary changes on CaBP content of maternal intestine and placenta and also on fetal mineral accumulation have been measured. Feeding high-calcium diets to pregnant mice decreased CaBP content in both maternal intestine and placenta (45 and 58%, respectively). Under these conditions of maternal hypercalcemia, fetal mineral accumulation was unchanged. In experiments with strontium-containing diets, CaBP content was reduced in both maternal intestine and placenta (66 and 67%, respectively), and fetal mineral accumulation was markedly reduced (70%). Administration of 1,25-dihydroxycholecalciferol [1,25(OH)2D] to the strontium-fed mice allowed the gestational rise in maternal intestinal CaBP to proceed to normal levels or above; however, the level of placental CaBP was not affected. Similarly, administration of 1,25(OH)2D to pregnant mice on a normal diet increased maternal intestinal CaBP, but had no effect upon placental CaBP. Thus, administration of 1,25(OH)2D to the mother, in amounts sufficient for a maternal intestinal response, was not a sufficient condition to increase placental production of CaBP.
为了研究肠道和胎盘钙结合蛋白（CaBP）的发育调控机制，我们通过给怀孕小鼠喂食高钙和高锶饮食来改变矿物质代谢。已经测量了这些饮食变化对母体肠道和胎盘CaBP含量以及胎儿矿物质积累的影响。给怀孕小鼠喂食高钙饮食会降低母体肠道和胎盘的CaBP含量（分别降低45%和58%）。在母体高钙血症的这些条件下，胎儿矿物质积累没有变化。在含锶饮食的实验中，母体肠道和胎盘的CaBP含量均降低（分别降低66%和67%），胎儿矿物质积累明显减少（70%）。给喂食锶的小鼠施用1,25 - 二羟胆钙化醇[1,25(OH)₂D]可使母体肠道CaBP的妊娠期升高恢复到正常水平或更高；然而，胎盘CaBP的水平不受影响。同样，给正常饮食的怀孕小鼠施用1,25(OH)₂D会增加母体肠道CaBP，但对胎盘CaBP没有影响。因此，给母体施用足以引起母体肠道反应量的1,25(OH)₂D，并不是增加胎盘CaBP产生的充分条件。
