Para-aminohippurate and Tetraethylammonium Transport in Fragments of Rat Renal Cortex

Goldin, Herzl; Zmudka, M.; Tio, Fermin O.; Vasquez, Angelina; Preuss, Harry G.

doi:10.3181/00379727-144-37664

Cited by 8 publications

(8 citation statements)

References 6 publications

(11 reference statements)

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“…We had previously found that PAH accumulation is significantly augmented at medium pH > 7.8 compared to medium pH 7.4 [2], Since the degree of enhancement to PAH accumulation in renal fragments in duced by 10 mM acetate (20-30%) is of the same magnitude as that produced by alkalo sis (medium pH > 7.8) alone (+20%), we hy pothesized that the in vitro effect of acetate on PAH uptake might be mediated in large part through the induced alkalosis [2], The present studies strengthen this hypo thesis. As previously reported [6], maximum tissue PAH uptake was reached by 30 min, and was maintained through 90 min when no substrate was present ( fig. 1).…”

Section: Discussionsupporting

confidence: 62%

“…There is no significant change in any T/M PAH after ether extraction under any given condition. mais with renal insufficiency [11][12][13][14], and enhance T/M PAH in renal slices [1, 15,16] and renal fragments [6], several hypotheses have been proposed to explain this phenom enon. Because there is a prompt effect of infused acetate on the T m PAH of dogs, Mudge and Taggart [12] proposed that it acts directly on the transfer process.…”

Section: Discussionmentioning

confidence: 99%

“…We cut thin cortical slices with a Stadic-Riggs microtome [5], and prepared cortical frag ments from them as previously described [6], These cortical fragments were washed in phosphate-buffered Cross and Taggart medium containing 40m M K* |!]. then approximately 0.1 g of these fragments were added to flasks containing 3 ml of Cross and Taggart medium plus I0~M/ 'H-PAH (/?-aminobenzoyl-2-3H-glycine: 50-150 mCi/mmol) or 10~5M PAH.…”

Section: Determination O F Pah Tissue Uptakementioning

confidence: 99%

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The Mechanism of Acetate Stimulation of PAH Transport in Rat Kidney Fragments

Kliger¹,

Hollyer²,

Preuss³

1982

Kidney Blood Press Res

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Accumulation of p-aminohippurate (PAH) by rat kidney fragments incubating in vitro is enhanced as medium pH rises from 7.4 toward 7.8. Since medium pH increases from 7.4 to 7.8 over a 90-min period in the presence of acetate, we were unsure whether acetate had any direct stimulatory effect on transport. Rat renal fragments incubating in acetate showed no enhanced PAH accumulation at 30 and 60 min when medium pH was less than 7.6 but did increase approximately 25% after 90 min when pH approached 7.8. By a number of different procedures, we consistently found that when medium pH was not allowed to rise, acetate did not stimulate PAH accumulation. We conclude that at an initial pH of 7.4, acetate stimulation of PAH uptake by rat kidney fragments during the course of a 90-min incubation can be explained almost entirely by a rise in pH to a more optimal range for transport. In contrast, stimulation of PAH accumulation by lactate and pyruvate cannot be explained solely by changes in medium pH.

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Section: Discussionsupporting

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Section: Determination O F Pah Tissue Uptakementioning

confidence: 99%

See 1 more Smart Citation

The Mechanism of Acetate Stimulation of PAH Transport in Rat Kidney Fragments

Kliger¹,

Hollyer²,

Preuss³

1982

Kidney Blood Press Res

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“…To assess [3H1 thymidine transport into renal fragments, two studies were performed in a manner used for p-aminohippurate (PAH) and tetraethylammonium (TEA) transport (5 tissue to medium rate ratio (T/M) was calculated by comparing the dpm in 1 g of fragments to the dpm in 1 ml of medium. In a second series of studies, extracts from rat kidney were investigated.…”

mentioning

confidence: 99%

A renotropic system in rats.

Preuss¹,

Goldin²

1976

J. Clin. Invest.

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“…The presence of sera, lactate and ace tate not only enhanced PAH accumulation in vitro [1,2], but increased pH from the initial 7.4 to 7.8-8.0. We were unsure what role this pH change played in the enhancement.…”

Section: Introductionmentioning

confidence: 99%

Effects of Medium pH on <i>p</i><i>-</i>Aminohippurate Transport in Rat Kidney Fragments

Kliger¹,

Resing²,

Eastman³

et al. 1978

Nephron

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Addition of many oxidizable substrates to medium often enhances p-aminohippurate (PAH) transport by incubating renal tissue. Since the oxidation of various substrates by rat kidney tissue may change medium pH and this pH change has not been considered by many in conclusions, we followed the effects of medium pH on the magnitude and kinetics of in vitro PAH transport. Two previous studies employing rat kidney slices reported different optimal medium pH for PAH accumulation, i.e. pH 6.5 and pH 8.0. By repeating these studies over a wide range of medium pH, we confirmed the presence of enhanced steady state accumulation relative to pH 7.4 at two separate pH ranges, one at pH 6.7–6.9 (+15%), and the other at pH 7.7–7.9 ( + 22%). PAH influx, as measured by early tissue accumulation, was not different at pH 7.4 and 7.8; while at pH 6.8, it actually decreased. It was only later in the incubation that accumulation was greater at pH 6.8 and 7.8. Probably due to the small stimulation in steady state accumulation at either pH, we could not discern, by the methodology currently available, if this was secondary to augmented influx, decreased efflux, or a combination of both in the latter part of incubation. We conclude that the contribution secondary to medium pH changes must be considered when evaluating the effects of various substrates on PAH accumulation by kidney slices.

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Para-aminohippurate and Tetraethylammonium Transport in Fragments of Rat Renal Cortex

Cited by 8 publications

References 6 publications

The Mechanism of Acetate Stimulation of PAH Transport in Rat Kidney Fragments

The Mechanism of Acetate Stimulation of PAH Transport in Rat Kidney Fragments

A renotropic system in rats.

Effects of Medium pH on <i>p</i><i>-</i>Aminohippurate Transport in Rat Kidney Fragments

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