Caverzasio J, Bonjour J P
Pflugers Arch. 1985 Jul;404(3):227-31. doi: 10.1007/BF00581243.
Previous studies have shown that the adaptive response of tubular inorganic phosphate (Pi) transport to Pi deprivation is detectable in the whole kidney 24 h after switching rats from a high (HPD) to a low (LPD) Pi diet. In the present work we report on a more rapid adaptive response of the sodium (Na)-dependent Pi transport system located in the luminal membrane of the proximal tubule and its relation with changes in phosphatemia an parathyroid hormone status. Rats were fed HPD and trained to eat their daily ration within 1 h. After two weeks of equilibration half of the animals received a single LPD ration. 1, 2 and 4 h after the end of food consumption the animals were either sacrificed for renal cortical brush border membrane vesicle (BBMV) isolation or used for determining plasma Pi concentration, urinary excretion of Pi and cAMP. The results indicate that 2 and 4 h after the end of feeding, the Na-dependent Pi transport in BBMV was stimulated by 70 and 140% respectively in intact rats exposed for the first time to LPD. This response was preceded by a significant fall in plasma Pi concentration (HPD: 2.46 +/- 0.03, LPD: 2.04 +/- 0.05 mM), in the urinary excretion of Pi (HPD: 899.0 +/- 68.1; LPD: 6.5 +/- 3.3 mumol/ml GFR) and cAMP (HPD: 76.9 +/- 7.4, LPD: 48.2 +/- 1.4 pmol/ml GF). This last result suggested a rapid inhibition of PTH after one single LPD feeding.(ABSTRACT TRUNCATED AT 250 WORDS)
先前的研究表明，将大鼠从高磷饮食（HPD）转换为低磷饮食（LPD）24小时后，在整个肾脏中可检测到肾小管无机磷酸盐（Pi）转运对Pi缺乏的适应性反应。在本研究中，我们报告了位于近端小管腔膜上的钠（Na）依赖性Pi转运系统的更快适应性反应及其与血磷和甲状旁腺激素状态变化的关系。给大鼠喂食HPD，并训练它们在1小时内吃完每日定量食物。平衡两周后，一半动物接受单次LPD定量食物。进食结束后1、2和4小时，将动物处死以分离肾皮质刷状缘膜囊泡（BBMV），或用于测定血浆Pi浓度、Pi尿排泄量和cAMP。结果表明，在首次暴露于LPD的完整大鼠中，进食结束后2小时和4小时，BBMV中Na依赖性Pi转运分别增加了70%和140%。这种反应之前，血浆Pi浓度显著下降（HPD：2.46±0.03，LPD：2.04±0.05 mM），Pi尿排泄量（HPD：899.0±68.1；LPD：6.5±3.3 μmol/ml GFR）和cAMP（HPD：76.9±7.4，LPD：48.2±1.4 pmol/ml GF）也显著下降。最后一个结果表明，单次LPD喂养后PTH迅速受到抑制。（摘要截断于250字）
