Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Phosphate transport  (4)
  • Sulfate transport  (4)
  • Lactate  (2)
  • Sodium Cotransport  (2)
  • 2-Oxolutarate-transport  (1)
Source
Material
Years
Keywords
  • 11
    Electronic Resource
    Electronic Resource
    Contraluminal para-aminohippurate (PAH) transport in the proximal tubule of the rat kidney (1987)
    Springer
    Pflügers Archiv 409 (1987), S. 229-235 
    Details
    ISSN: 1432-2013
    Keywords: 2-Oxoglutarate ; Lactate ; Pyruvate ; Nitrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to study the characteristics of contraluminal para-aminohippurate transport into proximal tubular cells the stopped flow capillary perfusion method was applied. The disappearance of3H-paraaminohippurate from the capillary perfusate at different concentrations and contact times was measured and saturation type behaviour was found with aK m of 0.08±0.01 (SE) mmol/l,J max of 1.1±0.1 pmol·s−1·cm−1 andr, the final extracellular/intracellular distribution ratio of 0.93±0.03. Omission of Na+ from the capillary test perfusate caused a small reduction of contraluminal PAH uptake at small transport rates (0.1 mmol/l PAH in the test perfusate) but not at high transport rates (1.0 mmol/l PAH in the test perfusate). Change of K+ between 0 and 40 mmol/l and pH between 6.0 and 8.0 did not influence contraluminal PAH uptake. Isotonic replacement of chloride by gluconate, nitrate, sulfate, phosphate, methanesulfonate or increase in bicarbonate to 50 mmol/l did not influence PAH uptake at small transport rates. But isotonic sulfate and phosphate, as well as 50 mmol/l HCO 3 − and 25 mmol/l Hepes in isotonic solutions reduced PAH uptake at high transport rates. Addition of 5 mmol/l Ca2+, Mg2+, Mn2+, Ba2+, Cd2+ to isotonic Na+-gluconate solution did not influence PAH uptake except for Mg2+ and Mn2+ which inhibited uptake at small transport rates only. Preperfusion of the peritubular capillaries with rat serum, Na+ gluconate (Ca2+-+Mg2+-free), Na+ gluconate (Ca2+-+Mg2+-free) plus 10 mmol/l lactate or pyruvate or 0.1 mmol/l 2-oxoglutarate did not influence PAH uptake at small PAH transport rates, but inhibited at high transport rates. Preperfusion of the capillaries for 10 s with Na+-, Ca2+- and Mg2+-free solutions reduced PAH uptake in the presence of Na+ at both transport rates. A second 10 s preperfusion — after the first 10 s Na+-, Ca2+-, Mg2+-free preperfusion — with serum or solutions which contained Na+ and Ca2+ or Mg2+ restored the PAH fluxes to control values. The data are compatible with the hypothesis that contraluminal PAH uptake occurs by a saturable transport mechanism in exchange for other intracellular anions rather than in cotransport with Na+ ions. It was, however, not possible to identify the type of counteranions involved. The large effect of cation replacement on para-aminohippurate transport, which was reported in many previous studies with kidney slices, is not a direct effect on the para-aminohippurate transporter, but is rather caused indirectly via cell metabolism and/or changed ion gradients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00583470
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Secretion and contraluminal uptake of dicarboxylic acids in the proximal convolution of rat kidney (1984)
    Springer
    Pflügers Archiv 400 (1984), S. 241-249 
    Details
    ISSN: 1432-2013
    Keywords: Basolateral cell membrane ; Methylsuccinate-transport ; 2-Oxolutarate-transport ; Citrate-transport ; Lithium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The transport of dicarboxylic acids in the proximal convolution was investigated by measuring: a) the zero net flux transtubular concentration difference ofdl-methyl-succinate, b) its 2-s influx from the interstitium into tubular cells, and c) its 3.5-s efflux from the tubular lumen. With the first method a luminal concentration exceeding the peritubular concentration was observed, thus indicating a net active transtubular secretion of this slowly metabolized substance. All transport steps, luminal and contraluminal, as well as the overall transport, were Na+-dependent and inhibited by lithium (apparentK i ≈ 1.8 mmol/l). The overall transport of methylsuccinate, as well as the contraluminal influx into proximal tubular cells, could be inhibited by paraaminohippurate and H2-DIDS with an apparentK i of ≈ 1.8 mmol/l, by taurocholate with an apparentK i ≈ 3.` mmol/l and by pyruvate with an apparentK i ≈ 5 mmol/l, but not by sulfate, thiosulfate,l-lactate, oxalate and urate. As judged from the inhibition of contraluminal methylsuccinate influx by 48 dicarboxylic acids (aliphatic and aromatic), a specificity pattern was observed similar to that of inhibition of luminal efflux of 2-oxoglutarate [22]: a preference of dicarboxylates in the transconfiguration with a chain length of 4–5 carbons; little change in the inhibitory potency with CH3 −, OH−, SH−and O=, but strong reduction with a NH 3 + in the 2 position; only a small reduction of inhibitory potency with 2,3 disubstituted SH and OH analogs; preference of the dicarboxylic benzene in the 1,4 position and of the diacetyl benzene in the 1,2 position. The data indicate a Na+-dependent dicarboxylic transport system at the contraluminal cell side of the proximal tubule which is very similar to the luminal transport system for dicarboxylic acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00581554
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Contraluminal para-aminohippurate (PAH) transport in the proximal tubule of the rat kidney (1988)
    Springer
    Pflügers Archiv 413 (1988), S. 134-146 
    Details
    ISSN: 1432-2013
    Keywords: Organic anion transport ; Sulfate transport ; Dicarboxylate transport ; Phenolate transport ; Salicylate transport ; Cinnamate transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to study the specificities of the contraluminal anion transport systems, the inhibitory potency of substituted benzene analogs on influx of [3H]PAH, [14C]succinate, and [35S]sulfate from the interstitium into cortical tubular cells has been determined in situ: (1) Contraluminal [3H]PAH influx is moderately inhibited by benzene-carboxylate and benzene-sulfonate, and strongly by benzene-dicarboxylates,-disulfonates and carboxy-benzene-sulfonates, if the substituents are located at positions 1 and 3 or 1 and 4. The affinity of the PAH transporter to polysubstituted benzoates increases with increasing hydrophobicity, decreasing electron density at the carboxyl group and decreasing pKa. Similar dependencies are observed for phenols. Benzaldehydes which do not carry an ionic negative charge are accepted by the PAH-transporter, if they possess a second partially charged aldehyde or NO2-group. (2) Contraluminal [14C]succinate influx is inhibited by benzene 1,3- or 1,4-dicarboxylates,-disulfonates and 1,3-or 1,4-carboxybenzene-sulfonates. Monosubstituted benzoates do not interact with the dicarboxylate transporter, but NO2-polysubstituted benzoates do. Phenol itself and 2-substituted phenol interact weakly possibly due to oligomer formation. (3) The contraluminal sulfate transporter interacts only with compounds which show a negative group accumulation such as 3,5-dinitro- or 3,5-dichloro-substituted salicylates. The data are consistent with three separate anion transport systems in the contraluminal membrane: The PAH transporter interacts with hydrophobic molecules carrying one or two negative charges (−COO−, −SO 3 − ) or two or more than two partial negative charges (−OH, −CHO, −SO2NH2, −NO2). The dicarboxylate transporter requires two electronegative ionic charges (−COO−, −SO 3 − ) at 5–9 Å distance or one ionic and several partial charges (−Cl, −NO2) at a favourable distance. The sulfate transporter interacts with molecules which have neighbouring electronegative charge accumulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582523
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...