Hruska K A, Klahr S, Hammerman M R
Am J Physiol. 1982 Jan;242(1):F17-22. doi: 10.1152/ajprenal.1982.242.1.F17.
To examine the effects of the hyperparathyroidism that accompanies chronic renal failure (CRF) on Pi transport across the renal proximal tubular luminal membrane, brush border membrane vesicles (BBMV) were prepared from the viable portion of the kidney of dogs with CRF or normal renal function. Initial rates of Na+ gradient-dependent Pi transport were decreased in BBMV from dogs with CRF compared with normal dogs. Initial rates of 22Na+ uptake in BBMV from dogs with CRF, however, were increased, suggesting a more rapid dissipation of the Na+ gradient in these vesicles. Initial rates of Pi transport measured under Na+-equilibrated conditions were decreased in BBMV from dogs with CRF. Parathyroidectomy of dogs with CRF abolished this decrease in Pi uptake. We conclude that the adaptations in Pi excretion associated with CRF are accompanied by changes in Na+-dependent Pi transport in BBMV and, therefore, possibly across the luminal membrane of the renal tubule. Moreover, the activity of this transport system can be altered by parathyroidectomy of dogs prior to isolation of BBMV.
为研究慢性肾衰竭（CRF）伴发的甲状旁腺功能亢进对磷通过肾近端小管腔膜转运的影响，从患有CRF或肾功能正常的犬的肾脏存活部分制备刷状缘膜囊泡（BBMV）。与正常犬相比，CRF犬的BBMV中钠梯度依赖性磷转运的初始速率降低。然而，CRF犬的BBMV中22Na+摄取的初始速率增加，表明这些囊泡中钠梯度的消散更快。在钠平衡条件下测量的CRF犬的BBMV中磷转运的初始速率降低。对CRF犬进行甲状旁腺切除可消除磷摄取的这种降低。我们得出结论，与CRF相关的磷排泄适应性变化伴随着BBMV中钠依赖性磷转运的变化，因此可能也伴随着肾小管腔膜上的变化。此外，在分离BBMV之前，对犬进行甲状旁腺切除可改变该转运系统的活性。
