Danisi G, Caverzasio J, Trechsel U, Bonjour J P, Straub R W
Dept. of Pharmacology, University Medical Center, Geneva, Switzerland.
Scand J Gastroenterol. 1990 Mar;25(3):210-5.
Intestinal absorption of inorganic phosphate (Pi) increases in response to a reduction in the dietary supply of Pi. In this work this adaptive response has been characterized in jejunal brush border membrane vesicles and studied in temporal relationship with the change in the plasma level of 1,25(OH)2D3. The results indicate that in rat jejunal brush border membrane vesicles the activity of the sodium-dependent Pi transport system is stimulated by a low Pi diet. This adaptive response was the result of an increase in the Vmax and a reduction in the Km of the cotransport system. This change in Pi transport was correlated with an increase in the circulating level of 1,25(OH)2D3 in a time-related fashion. In conclusion, these results are consistent with the notion that Pi restriction leads to an increase in Pi transport activity in the luminal membrane of the intestine. A time course study suggests that the elevation in plasma 1,25(OH)2D3 might be involved in the adaptation of the intestinal Pi transport system to Pi restriction.
无机磷酸盐（Pi）的肠道吸收会随着饮食中Pi供应的减少而增加。在这项研究中，这种适应性反应已在空肠刷状缘膜囊泡中得到表征，并与1,25(OH)2D3血浆水平的变化进行了时间关系研究。结果表明，在大鼠空肠刷状缘膜囊泡中，低磷饮食会刺激钠依赖性Pi转运系统的活性。这种适应性反应是共转运系统Vmax增加和Km降低的结果。Pi转运的这种变化与1,25(OH)2D3循环水平的时间相关增加有关。总之，这些结果与Pi限制导致肠道腔膜中Pi转运活性增加的观点一致。一项时间进程研究表明，血浆1,25(OH)2D3的升高可能参与了肠道Pi转运系统对Pi限制的适应。
