Phosphate transport in the proximal convolution of the rat kidney

1977 ◽  
Vol 372 (3) ◽  
pp. 269-274 ◽  
Author(s):  
K. J. Ullrich ◽  
G. Rumrich ◽  
S. Kl�ss
Keyword(s):  
Rat Kidney ◽  
Phosphate Transport ◽  
Proximal Convolution

Phosphate transport in the proximal convolution of the rat kidney

1978 ◽  
Vol 375 (1) ◽  
pp. 97-103 ◽  
Author(s):  
K. J. Ullrich ◽  
G. Rumrich ◽  
S. Kl�ss
Keyword(s):  
Rat Kidney ◽  
Phosphate Transport ◽  
Proximal Convolution

Phosphate transport in the proximal convolution of the rat kidney

1978 ◽  
Vol 377 (1) ◽  
pp. 33-42 ◽  
Author(s):  
K. J. Ullrich ◽  
G. Rumrich ◽  
S. Kl�ss
Keyword(s):  
Rat Kidney ◽  
Phosphate Transport ◽  
Proximal Convolution

Effect of fetal exposure to gentamicin on phosphate transport in young rat kidney

1993 ◽  
Vol 265 (6) ◽  
pp. F807-F812
Author(s):  
M. Lelievre-Pegorier ◽  
S. Euzet ◽  
C. Merlet-Benichou
Keyword(s):  
Brush Border Membrane ◽  
Rat Kidney ◽  
Total Phospholipid ◽  
Phospholipid Composition ◽  
Cholesterol Content ◽  
Phosphate Transport ◽  
Phospholipid Content ◽  
Postnatal Maturation ◽  
Rat Pups ◽  
Total Phospholipid Content

The renal phosphate (Pi)-transporting capacity normally increases, due to increased carrier system affinity, during the third postnatal week in rats. However, the tubular Pi reabsorption of rat pups born from gentamicin-treated mothers does not increase during this period. This study determines whether exposure to gentamicin in utero selectively alters the postnatal maturation of the carrier affinity for Pi. Pi and glucose transports by proximal tubule brush-border membrane (BBM) were studied. The maximal rate of uptake (Vmax) of Na-Pi cotransport was significantly lower (536 +/- 169 pmol.mg protein-1.10 s-1; n = 6, P < 0.01) in gentamicin-exposed rats than in controls (1,021 +/- 167 pmol.mg protein-1.10 s-1, n = 6), whereas the Michaelis constant (Km) values were the same. Gentamicin exposure had no effect on plasma parathyroid hormone concentration or on BBM glucose transport activity. The total phospholipid content of BBM, their phospholipid composition, cholesterol content, and cholesterol-to-total phospholipid mole ratio were unaltered, suggesting that membrane fluidity was unchanged. The Vmax of BBM alkaline phosphatase was lower in gentamicin-exposed rats than in controls.

scholarly journals Effects of an Early Weaning on Phosphate Transport Maturation in the Rat Kidney: Influence of the Phosphate Content of the Diet

1992 ◽  
Vol 32 (6) ◽  
pp. 704-709 ◽  
Author(s):  
Martine Lelievre-Pegorier ◽  
Bruno Leroy ◽  
Evelyne Moreau ◽  
Liliane Herpe-Patsouris ◽  
Claudie Merlet-Benichou
Keyword(s):  
Rat Kidney ◽  
Phosphate Transport ◽  
Phosphate Content ◽  
Early Weaning

scholarly journals pH gradient as an additional driving force in the renal re-absorption of phosphate

1990 ◽  
Vol 271 (3) ◽  
pp. 687-692 ◽  
Author(s):  
J Strévey ◽  
S Giroux ◽  
R Béliveau
Keyword(s):  
Driving Force ◽  
Phosphate Uptake ◽  
Rat Kidney ◽  
Membrane Vesicles ◽  
Phosphate Transport ◽  
Kidney Cortex ◽  
Rat Kidney Cortex ◽  
Total Phosphate Concentration ◽  
Combined Action ◽  
Phosphate Carrier

The effects of the Na+ gradient and pH on phosphate uptake were studied in brush-border membrane vesicles isolated from rat kidney cortex. The initial rates of Na(+)-dependent phosphate uptake were measured at pH 6.5, 7.5 and 8.5 in the presence of sodium gluconate. At a constant total phosphate concentration, the transport values at pH 7.5 and 8.5 were similar, but at pH 6.5 the influx was 31% of that at pH 7.5. However, when the concentration of bivalent phosphate was kept constant at all three pH values, the effect of pH was less pronounced; at pH 6.5, phosphate influx was 73% of that measured at pH 7.5. The Na(+)-dependent phosphate uptake was also influenced by a transmembrane pH difference; an outwardly directed H+ gradient stimulated the uptake by 48%, whereas an inwardly directed H+ gradient inhibited the uptake by 15%. Phosphate on the trans (intravesicular) side stimulated the Na(+)-gradient-dependent phosphate transport by 59%, 93% and 49%, and the Na(+)-gradient-independent phosphate transport by 240%, 280% and 244%, at pH 6.5, 7.5 and 8.5 respectively. However, in both cases, at pH 6.5 the maximal stimulation was seen only when the concentration of bivalent trans phosphate was the same as at pH 7.5. In the absence of a Na+ gradient, but in the presence of Na+, an outwardly directed H+ gradient provided the driving force for the transient hyperaccumulation of phosphate. The rate of uptake was dependent on the magnitude of the H+ gradient. These results indicate that: (1) the bivalent form of phosphate is the form of phosphate recognized by the carrier on both sides of the membrane; (2) protons are both activators and allosteric modulators of the phosphate carrier; (3) the combined action of both the Na+ (out/in) and H+ (in/out) gradients on the phosphate carrier contribute to regulate efficiently the re-absorption of phosphate.

Kinetic model for phosphate transport in renal brush-border membranes

1988 ◽  
Vol 254 (3) ◽  
pp. F329-F336 ◽  
Author(s):  
R. Beliveau ◽  
J. Strevey
Keyword(s):  
Brush Border ◽  
Rat Kidney ◽  
Membrane Vesicles ◽  
Phosphate Transport ◽  
Kidney Cortex ◽  
Binary Complex ◽  
Rat Kidney Cortex ◽  
First Time ◽  
Phosphate Influx ◽  
Phosphate Carrier

Phosphate transport was studied in brush-border membrane vesicles purified from rat kidney cortex. Influx and efflux were strongly dependent on the presence of cis sodium; the rate of efflux, calculated by linear regression performed on the first time points, was much lower than the rate of influx (0.044 vs. 0.198 pmol.microgram protein-1.s-1). Trans phosphate had a stimulatory effect on phosphate influx (145% stimulation at 10 mM phosphate trans, with 0.2 mM phosphate cis). Trans phosphate was, however, inhibitory for phosphate efflux (89% inhibition at 10 mM phosphate trans). Trans effects of sodium were also studied. With 200 mM trans sodium, we observed 73% inhibition of phosphate influx and 60% inhibition of phosphate efflux. Studies involving sodium and phosphate present at the same time as trans substrates showed that the trans inhibition of phosphate influx by sodium could be completely reversed by trans phosphate. Trans inhibition of phosphate efflux by phosphate was not additive to the inhibition caused by sodium. Addition of trans phosphate had a stimulatory effect on sodium-independent influx, indicating that the binary complex (C-P) could translocate in efflux. These results indicate that the renal phosphate carrier presents a random binding scheme for the intra- and extravesicular sides of the membrane.

scholarly journals Incorporation of d-glucose-, l-alanine- and phosphate-transport systems from rat renal brush-border membranes into liposomes

1977 ◽  
Vol 168 (2) ◽  
pp. 311-314 ◽  
Author(s):  
R Kinne ◽  
R G Faust
Keyword(s):  
Brush Border ◽  
Rat Kidney ◽  
Protein Composition ◽  
Phosphate Transport ◽  
Transport Systems ◽  
Brush Border Membranes ◽  
Naturally Occurring ◽  
Renal Brush Border Membranes ◽  
Triton X ◽  
Renal Brush Border

An extract of soluble proteins was prepared from a rat kidney brush-border membranes by Triton X-100 solubilization followed by centrifugation for 1 h at 100000g. Its protein composition was markedly different from that of the brush-border membranes. Proteoliposomes were formed by co-sonication of the Triton X-100-free extract with a naturally occurring mixture of phospholipids extracted from rat kidney. These proteoliposomes were shown to contain Na+-stimulated D-glucose-, L-alanine- and phosphate-transport systems.

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