Phosphate transport in immortalized cell cultures from the renal proximal tubule of normal and Hyp Mice: Evidence That the HYP gene locus product is an extrarenal factor

2009 ◽  
Vol 10 (9) ◽  
pp. 1327-1333 ◽  
Author(s):  
Teresa Nesbitt ◽  
Michael J. Econs ◽  
Jong K. Byun ◽  
Josée Martel ◽  
Harriet S. Tenenhouse ◽  
...  
Keyword(s):  
Proximal Tubule ◽  
Cell Cultures ◽  
Gene Locus ◽  
Phosphate Transport ◽  
Renal Proximal Tubule ◽  
Immortalized Cell ◽  
Locus Product

scholarly journals Signaling pathways utilized by PTH and dopamine to inhibit phosphate transport in mouse renal proximal tubule cells

2009 ◽  
Vol 296 (2) ◽  
pp. F355-F361 ◽  
Author(s):  
Rochelle Cunningham ◽  
Rajatsubhra Biswas ◽  
Marc Brazie ◽  
Deborah Steplock ◽  
Shirish Shenolikar ◽  
...  
Keyword(s):  
Proximal Tubule ◽  
Signaling Pathways ◽  
Phosphate Transport ◽  
Inhibitory Effect ◽  
Renal Proximal Tubule ◽  
Proximal Tubule Cells ◽  
Phosphate Cotransport ◽  
Tubule Cells ◽  
Renal Proximal Tubule Cells ◽  
Sodium Phosphate Cotransport

The present experiments were designed to detail factors regulating phosphate transport in cultured mouse proximal tubule cells by determining the response to parathyroid hormone (PTH), dopamine, and second messenger agonists and inhibitors. Both PTH and dopamine inhibited phosphate transport by over 30%. The inhibitory effect of PTH was completely abolished in the presence of chelerythrine, a PKC inhibitor, but not by Rp-cAMP, a PKA inhibitor. By contrast, both chelerythrine and Rp-cAMP blocked the inhibitory effect of dopamine. Chelerythrine inhibited PTH-mediated cAMP accumulation but also blocked the inhibitory effect of 8-bromo-cAMP on phosphate transport. On the other hand, Rp-cAMP had no effect on the ability of DOG, a PKC activator, to inhibit phosphate transport. PD98059, an inhibitor of MAPK, had no effect on PTH- or dopamine-mediated inhibition of sodium-phosphate cotransport. Finally, compared with 8-bromo-cAMP, 8-pCPT-2′- O-Me-cAMP, an activator of EPAC, had no effect on phosphate transport. These results outline significant differences in the signaling pathways utilized by PTH and dopamine to inhibit renal phosphate transport. Our results also suggest that activation of MAPK is not critically involved in PTH- or dopamine-mediated inhibition of phosphate transport in mouse renal proximal tubule cells in culture.

Phosphate uptake by primary renal proximal tubule cell cultures grown in hormonally defined medium

1985 ◽  
Vol 124 (3) ◽  
pp. 411-423 ◽  
Author(s):  
M. Anwar Waqar ◽  
Janny Seto ◽  
Soon Dong Chung ◽  
Sue Hiller-Grohol ◽  
Mary Taub
Keyword(s):  
Proximal Tubule ◽  
Cell Cultures ◽  
Phosphate Uptake ◽  
Defined Medium ◽  
Renal Proximal Tubule ◽  
Proximal Tubule Cell ◽  
Tubule Cell ◽  
Hormonally Defined Medium

Basolateral Phosphate Transport in Renal Proximal-Tubule-Like OK Cells1

2002 ◽  
Vol 227 (8) ◽  
pp. 626-631 ◽  
Author(s):  
M. Barac-Nieto ◽  
M. Alfred ◽  
A. Spitzer
Keyword(s):  
Proximal Tubule ◽  
Phosphate Transport ◽  
Renal Proximal Tubule ◽  
Passive Diffusion ◽  
Proximal Tubule Cells ◽  
Ok Cells ◽  
Anion Transporter ◽  
Tubule Cells ◽  
Acid Loading ◽  
Neutral Sodium

It is generally assumed that phosphate (Pi) effluxes from proximal tubule cells by passive diffusion across the basolateral (BL) membrane. We explored the mechanism of BL PI efflux in proximal tubule-like OK cells grown on permeable filters and then loaded with 32P. BL efflux of 32P was significantly stimulated (P < 0.05) by exposing the BL side of the monolayer to 12.5 mM Pi, to 10 mM citrate, or by acid-loading the cells, and was inhibited by exposure to 0.05 mM Pi or 25 mM HCO3; by contrast, BL exposure to high (8.4) pH, 40 mM K+, 140 mM Na gluconate (replacing NaCl), 10 mM lactate, 10 mM succinate, or 10 mM glutamate did not affect BL 32P efflux. These data are consistent with BL PI efflux from proximal tubule-like cells occurring, in part, via an electro-neutral sodium-sensitive anion transporter capable of exchanging two moles of intracellular acidic H2PO4– for each mole of extracellular basic HP04– or for citrate.

Defective PTH regulation of sodium-dependent phosphate transport in NHERF-1−/− renal proximal tubule cells and wild-type cells adapted to low-phosphate media

2005 ◽  
Vol 289 (4) ◽  
pp. F933-F938 ◽  
Author(s):  
Rochelle Cunningham ◽  
Xiaofei E ◽  
Deborah Steplock ◽  
Shirish Shenolikar ◽  
Edward J. Weinman
Keyword(s):  
Proximal Tubule ◽  
Primary Cultures ◽  
Phosphate Transport ◽  
Inhibitory Response ◽  
Renal Proximal Tubule ◽  
Wild Type ◽  
Proximal Tubule Cells ◽  
Sodium Dependent ◽  
Tubule Cells ◽  
Renal Proximal Tubule Cells

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.

Control of phosphate transport in flounder renal proximal tubule primary cultures

1989 ◽  
Vol 256 (4) ◽  
pp. R850-R857 ◽  
Author(s):  
A. Gupta ◽  
J. L. Renfro
Keyword(s):  
Proximal Tubule ◽  
Primary Cultures ◽  
Phosphate Transport ◽  
Renal Proximal Tubule ◽  
Pseudopleuronectes Americanus ◽  
Ussing Chambers ◽  
Long Latency ◽  
Phosphate Availability ◽  
Phosphate Fluxes ◽  
Renal Proximal Tubule Cells

Unidirectional mucosal-to-serosal (Jm----s) and serosal-to-mucosal (Js----m) transepithelial phosphate fluxes across monolayers of flounder (Pseudopleuronectes americanus) renal proximal tubule cells in primary culture were examined for effects of diacylglycerols, phorbol ester, A23187, forskolin, and extracellular phosphate availability. Tissues were cultured on floating collagen rafts and studied short circuited in Ussing chambers. Transepithelial electrical properties were continuously monitored and were unaffected by any of the treatments compared with paired controls. Under usual conditions (phosphate = 0.4 mM) tissues invariably displayed net phosphate reabsorption [Js----m = 2.3 +/- 0.52; Jm----a = 7.1 +/- 1.77; Jnet = 4.9 +/- 1.45 (SE) nmol.cm-2.h-1]. Acute elevation of bath phosphate concentration above 0.5 mM stimulated net secretion. Exposure to 100 microM 1,2-dihexanoyl-sn-glycerol stimulated net phosphate secretion within 30 min, the result of a fivefold increase in Js----m. Phorbol-12,13-didecanoate stimulated net phosphate secretion by increasing Js----m and decreasing Jm----s. The inactive diacylglycerol, 1,3-didecanoyl-rac-glycerol (100 microM), had no effect on phosphate fluxes. A23187 stimulated net phosphate secretion; Jm----s was reduced almost fourfold while Js----m was increased threefold. Forskolin (10 microM) stimulated net reabsorption more than threefold after a long latency (2 h). These data indicate that renal phosphate secretion and reabsorption may be regulated by several putative intracellular messengers. In addition, extracellular phosphate availability may modulate renal phosphate handling.

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