| First Author | Cunningham R | Year | 2005 |
| Journal | Am J Physiol Renal Physiol | Volume | 289 |
| Issue | 4 | Pages | F933-8 |
| PubMed ID | 15942053 | Mgi Jnum | J:101246 |
| Mgi Id | MGI:3603500 | Doi | 10.1152/ajprenal.00005.2005 |
| Citation | Cunningham R, et al. (2005) Defective PTH regulation of sodium-dependent phosphate transport in NHERF-1-/- renal proximal tubule cells and wild-type cells adapted to low-phosphate media. Am J Physiol Renal Physiol 289(4):F933-8 |
| abstractText | The present experiments using primary cultures from renal proximal tubule cells examine two aspects of the regulation of sodium-dependent phosphate transport and membrane sodium-dependent phosphate transporter (Npt2a) expression by parathyroid hormone (PTH). Sodium-dependent phosphate transport in proximal tubule cells from wild-type mice grown in normal-phosphate media averaged 4.4 +/- 0.5 nmol.mg protein(-1).10 min(-1) and was inhibited by 30.5 +/- 8.6% by PTH (10(-7) M). This was associated with a 32.7 +/- 5.2% decrease in Npt2a expression in the plasma membrane. Proximal tubule cells from Na(+)/H(+) exchanger regulatory factor-1 (NHERF-1)(-/-) mice had a lower rate of phosphate transport compared with wild-type cells and a significantly reduced inhibitory response to PTH. Wild-type cells incubated in low-phosphate media for 24 h had a higher rate of phosphate transport compared with wild-type cells grown in normal-phosphate media but a significantly blunted inhibitory response to PTH. These data indicate a role for NHERF-1 in mediating the membrane retrieval of Npt2a and the subsequent inhibition of phosphate transport in renal proximal tubules. These studies also suggest that there is a blunted phosphaturic effect of PTH in cells adapted to low-phosphate media. |
