Grases F, Simonet B M, March J G, Prieto R M
Laboratory of Renal Lithiasis Research, University of the Belearic Islands, Palma de Mallorca, Spain.
BJU Int. 2000 Jan;85(1):138-42. doi: 10.1046/j.1464-410x.2000.00324.x.
To study the relationship between the oral intake of inositol hexakisphosphate (InsP6, phytic acid, an inhibitor of urinary crystallization) and its urinary excretion, to establish their possible mutual influence.
Two groups of male Wistar rats (six animals each) received either; tap water and normal rat food pellets (controls); or a liquid diet in which InsP6 was absent and which then received gradually increasing amounts of InsP6. The urinary levels of InsP6 were then assessed regularly in both groups.
When InsP6 was absent from the diet, urinary excretion declined to undetectable levels after 22 days. The addition of increasing amounts of InsP6 to the liquid diet caused an increase in its urinary excretion after about 10 days. Adding InsP6 in amounts > 425 mg/L caused no further increases in urinary excretion. Adding inositol (with no InsP6) to the liquid diet caused only a slight increase in the urinary excretion of InsP6.
These results showed that InsP6 urinary levels were related to its oral intake; consequently, a low consumption of InsP6 would cause a urinary deficit of this crystallization inhibitor and thus an increase in the risk of developing urinary calcium stones. Although urinary excretion was dose-dependent, there was an ingested amount (20.9 mg/kg) above which there was no increase in the amount excreted. This intake is easily obtained by consuming a normal diet (rich in InsP6) indicating that to maintain appropriate urinary levels of InsP6, the consumption of InsP6 supplements is only necessary when the diet is particularly poor in InsP6.
研究口服肌醇六磷酸（InsP6，植酸，一种尿结晶抑制剂）与其尿排泄之间的关系，以确定它们可能的相互影响。
两组雄性Wistar大鼠（每组6只）分别接受：自来水和正常大鼠食丸（对照组）；或不含InsP6的流质饮食，然后逐渐增加InsP6的摄入量。随后定期评估两组大鼠尿液中InsP6的水平。
当饮食中不含InsP6时，22天后尿排泄量降至检测不到的水平。在流质饮食中添加越来越多的InsP6，约10天后其尿排泄量增加。添加量>425mg/L的InsP6不会使尿排泄量进一步增加。在流质饮食中添加肌醇（不含InsP6）只会使InsP6的尿排泄量略有增加。
这些结果表明，InsP6的尿水平与其口服摄入量有关；因此，InsP6摄入量低会导致这种结晶抑制剂的尿缺乏，从而增加患尿钙结石的风险。虽然尿排泄呈剂量依赖性，但存在一个摄入剂量（20.9mg/kg），超过该剂量后排泄量不再增加。通过食用正常饮食（富含InsP6）很容易获得这一摄入量，这表明要维持适当的InsP6尿水平，只有在饮食中InsP6特别缺乏时才需要补充InsP6。
