Effect of phosphonoformic acid, dietary phosphate and the Hyp mutation on kinetically distinct phosphate transport processes in mouse kidney

1989 ◽  
Vol 984 (2) ◽  
pp. 207-213 ◽  
Author(s):  
Harriet S. Tenenhouse ◽  
Abbey H. Klugerman ◽  
Jack L. Neal
Keyword(s):  
Phosphate Transport ◽  
Mouse Kidney ◽  
Transport Processes ◽  
Phosphonoformic Acid ◽  
Dietary Phosphate

Phosphate Transport Processes of Animal Cells

1982 ◽  
pp. 645-663 ◽  
Author(s):  
Peter L. Pedersen ◽  
Janna P. Wehrle
Keyword(s):  
Phosphate Transport ◽  
Transport Processes ◽  
Animal Cells

Phosphate uptake by renal membrane vesicles of rabbits adapted to high and low phosphorus diets

1983 ◽  
Vol 245 (2) ◽  
pp. F175-F180 ◽  
Author(s):  
L. Cheng ◽  
C. T. Liang ◽  
B. Sacktor
Keyword(s):  
Transport System ◽  
Phosphate Uptake ◽  
Membrane Vesicles ◽  
Phosphate Transport ◽  
Uptake System ◽  
Low Phosphorus ◽  
Dietary Phosphate ◽  
Preferred Species ◽  
Uptake Medium ◽  
Phosphate Carrier

Renal adaptation to changes in phosphate intake was studied by comparing phosphate uptake by proximal tubule brush border membrane vesicles from rabbits on a relatively high or low phosphorus diet. The low phosphorus diet increased Na+ gradient-dependent phosphate uptake. Uptake in the absence of Na+ and in the presence of Na+, but no gradient, was not significantly affected. The phosphorus diet did not alter Na+ gradient-dependent D-glucose and L-proline uptake. The low phosphorus diet increased Vmax; affinity for phosphate was not appreciably changed. At all concentrations of extravesicular Na+, phosphate uptake was higher in membrane vesicles from animals fed the low phosphorus diet; the kinetics of the phosphate uptake system, with respect to Na+, was also altered by the change in dietary phosphate. These findings suggest that adaptation involves an alteration in the rate of translocation of the Na+-phosphate carrier when energized by a Na+ gradient driving force rather than a change in the number of Na+-phosphate carrier sites. With membrane vesicles from rabbits fed a low phosphorus diet, phosphate uptake increased several-fold when the pH of the uptake medium was raised, whereas with membrane vesicles from animals fed a high phosphorus diet the enhancement of uptake with alkalinization was relatively small. Irrespective of the diet, divalent phosphate was the probable preferred species for transport. Dietary adaptation was associated, however, with an alteration in the pH dependency of the transport system per se. These findings provide evidence that the adaptation of the kidney phosphate transport system to dietary phosphate load involves an intrinsic change in the Na+-phosphate carrier.

scholarly journals Dopamine enhances the phosphaturic response to parathyroid hormone in phosphate-deprived rats.

1992 ◽  
Vol 2 (9) ◽  
pp. 1423-1429
Author(s):  
J Isaac ◽  
T J Berndt ◽  
S L Chinnow ◽  
G M Tyce ◽  
T P Dousa ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Fractional Excretion ◽  
Phosphate Transport ◽  
Dopamine Synthesis ◽  
Dopamine Infusion ◽  
Phosphate Deprivation ◽  
Dietary Phosphate ◽  
Urinary Dopamine ◽  
Fractional Excretion Of Phosphate ◽  
High Phosphate

Phosphate deprivation results in a resistance to the phosphaturic effect of parathyroid hormone. Dopamine is phosphaturic and is synthesized by kidney proximal tubule, the nephron subsegment where parathyroid hormone inhibits phosphate transport. Thus, to test the hypothesis that phosphate deprivation is associated with low intrarenal dopamine synthesis and that dopamine infusion will overcome the resistance to the phosphaturic response to parathyroid hormone, the following study was performed. The effect of dietary phosphate intake on intrarenal dopamine synthesis, as reflected by urinary dopamine excretion, was determined. Rats were placed in metabolic cages (N = 5) and were fed a low-phosphate diet (0.07% Pi) for 4 days and then a high-phosphate diet (1.8% Pi) for 4 days. Twenty-four-hour urinary dopamine excretion was significantly lower in rats fed a low-phosphate diet (2.53 +/- 0.06 versus 4.10 +/- 0.30 micrograms/day). Further, the effect of dopamine infusion on the blunted phosphaturic response to parathyroid hormone was studied in rats fed a low-phosphate diet for 1, 2, and 3 days. Control clearances were taken 2 h after thyroparathyroidectomy; then, parathyroid hormone (33 U/kg plus 1 U/kg/min), dopamine (25 micrograms/kg/min), or parathyroid hormone plus dopamine were infused for 60 min. Changes in the fractional excretion of phosphate were significantly greater in rats fed a low-phosphate diet infused with parathyroid hormone plus dopamine than in rats fed a low-phosphate diet infused with parathyroid hormone alone (delta 27.9 +/- 5.8 versus 11.2 +/- 2.6% for day 1; 28.4 +/- 1.4 versus 7.1 +/- 3.6% for day 2; and 10.7 +/- 2.8 versus -0.2 +/- 0.2% for day 3; N = 5 for all groups).(ABSTRACT TRUNCATED AT 250 WORDS)

An established cell line from mouse kidney medullary thick ascending limb. I. Cell culture techniques, morphology, and antigenic expression

1986 ◽  
Vol 251 (2) ◽  
pp. C299-C311 ◽  
Author(s):  
J. D. Valentich ◽  
M. F. Stokols
Keyword(s):  
Cell Line ◽  
Proteolytic Enzymes ◽  
Mouse Kidney ◽  
Transport Processes ◽  
Model Systems ◽  
Established Cell Line ◽  
Epithelial Cell Line ◽  
Thick Ascending Limb ◽  
Culture Techniques ◽  
Medullary Thick Ascending Limb

The effective use of cultured cells as model systems for investigating the differentiation and regulation of transport processes in renal tubular epithelial cells depends on the availability of functional long-term cell lines derived from specific nephron segments. Conventional culture procedures that treat cells as proliferating microorganisms possess several inherent limitations that could contribute to phenotypic instability and limited proliferative capacity in vitro. In this study, culture techniques were adopted that avoid exposure of cells to proteolytic enzymes, maintain intercellular contacts, and allow cells to remain continually adherent to a collagen gel substratum. This methodology resulted in the development of a continuous epithelial cell line from identified, microdissected segments of the mouse kidney medullary thick ascending limb.

Presence of multiple sodium-dependent phosphate transport processes in proximal brush-border membrane

1987 ◽  
Vol 252 (2) ◽  
pp. F226-F231 ◽  
Author(s):  
J. J. Walker ◽  
T. S. Yan ◽  
G. A. Quamme
Keyword(s):  
Proximal Tubule ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Phosphate Transport ◽  
Transport Processes ◽  
Proximal Tubules ◽  
High Affinity ◽  
Medullary Tissue ◽  
Sodium Dependent ◽  
Early Proximal Tubule

Renal brush-border membrane phosphate transport was studied in early and late segments of the pig proximal tubule. Vesicles were prepared from early proximal tubules (outer cortical tissue) and late proximal tubules (outer medullary tissue). Sodium-dependent phosphate uptake into brush-border membrane vesicles was determined using voltage clamp at 5-6 s, 21 degrees C. Sodium-dependent D-glucose uptake was determined to verify the cortical and medullary tissue cuts. At pH 8.0 (pHi = pHo), two sodium-dependent phosphate transport systems were evident in the early proximal tubule: a high-affinity system [Km, 0.06 +/- 0.01 mM; maximal transport activity (Vmax), 3.6 +/- 1.1 nmol X mg protein-1 X min-1] and a low-affinity system (Km, 4.11 +/- 0.02 mM; Vmax, 9.7 +/- 0.7 nmol X mg protein-1 X min-1). In the late proximal tubule at pH 8.0, only a single high-affinity transport process (Km, 0.19 +/- 0.7 mM; Vmax, 3.4 +/- 0.5 nmol X mg protein-1 X min-1) was evident. D-Glucose kinetics at pH 7.0 revealed both a high-affinity (Km, 0.55 +/- 0.09 mM) and a low-affinity (Km, 20.09 +/- 1.39 mM) system in the early proximal segment and a single high-affinity (Km, 1.27 +/- 0.36 mM) process in the late segment. These data suggest that two systems, distinct in their affinities and capacities, are involved in both D-glucose and phosphate transport across the brush-border membrane of the early proximal tubule, but that only a single high-affinity system is present in the late segment.

Brefeldin A inhibits phosphate transport in opossum kidney cells

1993 ◽  
Vol 264 (1) ◽  
pp. C40-C47 ◽  
Author(s):  
A. W. Capparelli ◽  
M. C. Heng ◽  
L. Li ◽  
O. D. Jo ◽  
N. Yanagawa
Keyword(s):  
Protein Synthesis ◽  
Golgi Apparatus ◽  
Phosphate Uptake ◽  
Brefeldin A ◽  
Phosphate Transport ◽  
Transport Processes ◽  
Free Medium ◽  
Opossum Kidney ◽  
Ok Cells ◽  
Phosphate Deprivation

Brefeldin A (BFA) is a fungal metabolite that blocks the transport processes between the endoplasmic reticulum and the Golgi apparatus. In the present study, we have tested the effect of BFA on phosphate transport in a kidney epithelial cell line, opossum kidney (OK) cells. Electron microscopy showed that exposure of OK cells to BFA caused a rapid and reversible disorganization of Golgi apparatus. Addition of BFA also caused a time (2-8 h)- and dose (1-10 micrograms/ml)-dependent inhibition of Na(+)-dependent cell phosphate uptake. The inhibition of cell phosphate uptake by BFA was reversible and was associated with a decrease in the maximum velocity of phosphate transport. Both the inhibition and the stimulation of cell phosphate uptake by parathyroid hormone and insulin, respectively, were not affected by BFA. BFA at 1 microgram/ml concentration did not affect protein synthesis as determined by [3H]leucine incorporation but diminished the adaptive increase in cell phosphate uptake in response to 2 or 8 h of incubation in nominally phosphate-free medium. On the other hand, inhibition of protein synthesis by cycloheximide (5 microM) abolished the adaptive increase in cell phosphate uptake in response to 8 but not 2 h of incubation in nominally phosphate-free medium, indicating the existence of an early response to phosphate deprivation, which does not require new protein synthesis but is sensitive to the effect of BFA. In summary, results of these studies show that, in OK cells, BFA inhibits phosphate uptake and curtails the adaptive response to phosphate deprivation.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Alkaline phosphatase activity does not mediate phosphate transport in the renal-cortical brush-border membrane

1980 ◽  
Vol 190 (2) ◽  
pp. 473-476 ◽  
Author(s):  
H S Tenenhouse ◽  
C R Scriver ◽  
E J Vizel
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Phosphate Transport ◽  
Mouse Kidney ◽  
Brush Border Membrane Vesicles ◽  
Low Phosphorus

We studied (1) the effect of primary modulators of phosphate transport, namely the hypophosphataemic mouse mutant (Hyp) and low-phosphorus diet, on alkaline phosphatase activity in mouse renal-cortex brush-border membrane vesicles and (2) the effect of several primary inhibitors of alkaline phosphatase on phosphate transport. Brush-border membrane vesicles from Hyp-mouse kidney had 50% loss of Na+-dependent phosphate transport, but only 18% decrease in alkaline phosphatase activity. The low-phosphorus diet effectively stimulated Na+/phosphate co-transport in brush-border membrane vesicles (+ 118%), but increased alkaline phosphatase activity only slightly (+13%). Levamisole (0.1 mM) and EDTA (1.0 mM) inhibited brush-border membrane-vesicle alkaline phosphatase activity of 82% and 93% respectively, but had no significant effect on Na+/phosphate co-transport. We conclude that alkaline phosphatase does not play a direct role in phosphate transport across the brush-border membrane of mouse kidney.

Characterization of inorganic phosphate transport in osteoclast-like cells

2005 ◽  
Vol 288 (4) ◽  
pp. C921-C931 ◽  
Author(s):  
Mikiko Ito ◽  
Naoko Matsuka ◽  
Michiyo Izuka ◽  
Sakiko Haito ◽  
Yuko Sakai ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Transport System ◽  
Inorganic Phosphate ◽  
Phosphate Transport ◽  
Transport Systems ◽  
Raw264.7 Cells ◽  
Transport Activity ◽  
Phosphonoformic Acid ◽  
Carbonyl Cyanide ◽  
Bone Particles

Osteoclasts possess inorganic phosphate (Pi) transport systems to take up external Pi during bone resorption. In the present study, we characterized Pi transport in mouse osteoclast-like cells that were obtained by differentiation of macrophage RAW264.7 cells with receptor activator of NF-κB ligand (RANKL). In undifferentiated RAW264.7 cells, Pi transport into the cells was Na+ dependent, but after treatment with RANKL, Na+-independent Pi transport was significantly increased. In addition, compared with neutral pH, the activity of the Na+-independent Pi transport system in the osteoclast-like cells was markedly enhanced at pH 5.5. The Na+-independent system consisted of two components with Km of 0.35 mM and 7.5 mM. The inhibitors of Pi transport, phosphonoformic acid, and arsenate substantially decreased Pi transport. The proton ionophores nigericin and carbonyl cyanide p-trifluoromethoxyphenylhydrazone as well as a K+ ionophore, valinomycin, significantly suppressed Pi transport activity. Analysis of BCECF fluorescence indicated that Pi transport in osteoclast-like cells is coupled to a proton transport system. In addition, elevation of extracellular K+ ion stimulated Pi transport, suggesting that membrane voltage is involved in the regulation of Pi transport activity. Finally, bone particles significantly increased Na+-independent Pi transport activity in osteoclast-like cells. Thus, osteoclast-like cells have a Pi transport system with characteristics that are different from those of other Na+-dependent Pi transporters. We conclude that stimulation of Pi transport at acidic pH is necessary for bone resorption or for production of the large amounts of energy necessary for acidification of the extracellular environment.

Phosphate homeostasis and the renal-gastrointestinal axis

2010 ◽  
Vol 299 (2) ◽  
pp. F285-F296 ◽  
Author(s):  
Joanne Marks ◽  
Edward S. Debnam ◽  
Robert J. Unwin
Keyword(s):  
Small Intestine ◽  
Phosphate Transport ◽  
Phosphate Absorption ◽  
Renal Phosphate Reabsorption ◽  
Sodium Dependent ◽  
Dietary Phosphate ◽  
Intestinal Phosphate Absorption ◽  
End Stage ◽  
And Control ◽  
Renal Phosphate Excretion

Transport of phosphate across intestinal and renal epithelia is essential for normal phosphate balance, yet we know less about the mechanisms and regulation of intestinal phosphate absorption than we do about phosphate handling by the kidney. Recent studies have provided strong evidence that the sodium-phosphate cotransporter NaPi-IIb is responsible for sodium-dependent phosphate absorption by the small intestine, and it might be that this protein can link changes in dietary phosphate to altered renal phosphate excretion to maintain phosphate balance. Evidence is also emerging that specific regions of the small intestine adapt differently to acute or chronic changes in dietary phosphate load and that phosphatonins inhibit both renal and intestinal phosphate transport. This review summarizes our current understanding of the mechanisms and control of intestinal phosphate absorption and how it may be related to renal phosphate reabsorption; it also considers the ways in which the gut could be targeted to prevent, or limit, hyperphosphatemia in chronic and end-stage renal failure.

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