Weinreb S, Hruska K A, Klahr S, Hammerman M R
Am J Physiol. 1982 Jul;243(1):F29-35. doi: 10.1152/ajprenal.1982.243.1.F29.
After release of complete unilateral ureteral obstruction, a decreased fractional excretion of phosphate (Pi) is observed in the postobstructed kidney compared with the nonobstructed (control) kidney. To determine whether this decrease in the urinary excretion of Pi is due to changes in Na+-dependent Pi transport across the renal brush border membranes of postobstructed and control kidneys, membrane vesicles were prepared from the brush borders of kidneys from dogs that had undergone complete unilateral ureteral obstruction. Alkaline phosphatase activity was decreased in membrane vesicles isolated from postobstructed kidneys. No differences were observed in Na+-dependent Pi transport or in Na+ uptake in membrane vesicles isolated from postobstructed as compared with control kidneys. The in vivo administration of parathyroid hormone decreased Na+-dependent Pi transport in membrane vesicles isolated from postobstructed and control kidneys despite the absence of a phosphaturic response. Our findings suggest that no intrinsic change in the transport characteristics of Pi across the luminal membrane of renal tubular cells occurs with unilateral ureteral obstruction. The findings are consistent with the suggestion that the low fractional excretion of Pi in the postobstructed kidney results from very low filtered loads of Pi on the postobstructed side.
在完全性单侧输尿管梗阻解除后，与未梗阻（对照）肾相比，梗阻后肾的磷酸盐（Pi）排泄分数降低。为了确定Pi尿排泄的减少是否是由于梗阻后肾和对照肾的肾刷状缘膜上Na⁺依赖性Pi转运的变化所致，从经历过完全性单侧输尿管梗阻的犬的肾刷状缘制备了膜囊泡。从梗阻后肾分离的膜囊泡中碱性磷酸酶活性降低。与对照肾相比，从梗阻后肾分离的膜囊泡中，在Na⁺依赖性Pi转运或Na⁺摄取方面未观察到差异。尽管没有磷尿反应，但体内给予甲状旁腺激素会降低从梗阻后肾和对照肾分离的膜囊泡中Na⁺依赖性Pi转运。我们的研究结果表明，单侧输尿管梗阻时，Pi跨肾小管细胞腔面膜的转运特性没有内在变化。这些结果与以下观点一致，即梗阻后肾中Pi排泄分数低是由于梗阻后侧Pi的滤过负荷非常低。
