Exchangeability of chloride in Ehrlich ascites tumor cells

Simonsen, Leif; Nielsen, Anne-Mette T.

doi:10.1016/0005-2736(71)90051-4

Cited by 27 publications

(2 citation statements)

References 13 publications

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“…(The perchloric acid extraction procedure gives the same results for cell sodium and potassium content as the distilled water extraction used by Hempling (1962), Kromphardt (1968) and others. However, the chloride content is some 20 % less with perchloric acid extraction and, with this technique, cell chloride is found to exchange completely with radioactive chloride in the environment (Simonsen & Nielsen, 1971). I am grateful to Harold G. Hempling for bringing this to my attention.)…”

Section: Experimental Deignmentioning

confidence: 98%

The effect of external anions on steady‐state chloride exchange across ascites tumour cells

Aull¹

1972

The Journal of Physiology

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1. The rate of cell chloride exchange, or efflux coefficient, was measured after equilibration in media of different anionic composition. 2. When sulphate substituted for chloride in the medium, the efflux coefficient was always higher than in control chloride solutions and varied inversely with external chloride concentration. In sulphate the chloride efflux coefficient varied from 19·6 to 100·7 hr−1. The mean control efflux coefficient was 6·60 ± 0·677 ( S.E. of mean). 3. In contrast, when external nitrate substituted for chloride, the efflux coefficient was independent of external chloride concentration and the same as in control chloride media. The mean value in nitrate was 6·42 ± 0·603 ( S.E. of mean). The results confirm findings of Hempling & Kromphardt (1965). 4. Steady‐state chloride flux varied in direct proportion to the external chloride concentration, which would be expected for passive chloride exchange. However, the slope of the line relating these variables was higher in sulphate than in nitrate and control media. Thus at any given external chloride concentration chloride flux was greater in sulphate than in nitrate and control solutions. 5. It is suggested that the effect of sulphate to increase cell chloride exchange may be related to its greater tendency to bind water, relative to chloride and nitrate.

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Section: Experimental Deignmentioning

confidence: 98%

The effect of external anions on steady‐state chloride exchange across ascites tumour cells

Aull¹

1972

The Journal of Physiology

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“…The chloride steady-state exchange flux was measured as unidirectional influx (as described by Simonsen & Nielsen, 1971), or as unidirectional efflux (as described by Hoffmann et al, 1979). The tracer exchange experiments were performed under steadystate conditions and the kinetics in the individual experiments were well described by a closed two-compartment model with constant volumes.…”

Section: Ci-flux Experimentsmentioning

confidence: 99%

Identification of the anion exchange protein of ehrlich cells: A kinetic analysis of the inhibitory effects of 4,4′-diisothiocyano-2,2′-stilbene-disulfonic acid (DIDS) and labeling of membrane proteins with3H-DIDS

1986

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In Ehrlich ascites tumor cells 4,4'-diisothiocyano-2,2'-stilbene-disulfonic acid (DIDS) inhibits the chloride exchange both reversibly and irreversibly. The reversible inhibition is practically instantaneous and of a competitive nature with Ki about 2 microM at zero chloride concentration. This is succeeded by a slow irreversible binding of DIDS to the transporter, with a chloride dependence suggesting binding to the same site as for reversible DIDS binding/inhibition. To identify the membrane protein involved in anion exchange, cells were labeled with 3H-DIDS. Incubation of cells for 10 min with 25 microM DIDS at pH 8.2 leads to more than 95% inhibition of the DIDS-sensitive chloride exchange flux when the chloride concentration is low (15 mM). This condition was used for the 3H-DIDS-labeling experiments. After incubation the cells were disrupted, the membranes isolated and solubilized, and the proteins separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The distribution of the 3H-activity in the gel showed only one major peak, which could be related to protein with a mol wt of about 30,000 Daltons. The number of transport sites was estimated at about 400,000 per cell, and from the DIDS-sensitive chloride flux under steady-state conditions we calculate a turnover number of 340 ions per sec per site.

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Anion transport in the Ehrlich ascites tumor cell: The effect of 2,4,6‐trinitrobenzene sulfonic acid

Levinson

Villereal

1973

Journal Cellular Physiology

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We have investigated the effects of the amino reactive reagent, 2,4,6-trinitrobenzene sulfonic acid (TNBS) on anion transport (chloride and sulfate) and on the K+ content of Ehrlich ascites tumor cells. Incubation of tumor cells with TNBS (3 mM or 10 mM) results in a time dependent uptake of this molecule. Tightly bound TNBS caused a loss of K+ as well as inhibition of sulfate uptake. Although sulfate transport was inhibited by tightly bound TNBS (40% inhibition with 20 nmoles bound per lo7 cells), reversibly bound TNBS exerted much greater inhibition. Kinetic analysis of sulfate transport in the presence and absence of TNBS suggests that: (1) tightly bound TNBS exerts a competitive inhibition by occupying membrane sites remote from the specific transport site, (2) TNBS reversibly interacts with a separate site also in a competitive fashion.Increasing amounts of tightly bound TNBS resulted in a n enhanced chloride influx. However, reversibly bound TNBS was without effect. These results are i n contrast to the effect of TNBS on sulfate transport and show that TNBS, at least in this cell type, is not a general inhibitor of anion transport.

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Exchangeability of chloride in Ehrlich ascites tumor cells

Cited by 27 publications

References 13 publications

The effect of external anions on steady‐state chloride exchange across ascites tumour cells

The effect of external anions on steady‐state chloride exchange across ascites tumour cells

Identification of the anion exchange protein of ehrlich cells: A kinetic analysis of the inhibitory effects of 4,4′-diisothiocyano-2,2′-stilbene-disulfonic acid (DIDS) and labeling of membrane proteins with3H-DIDS

Anion transport in the Ehrlich ascites tumor cell: The effect of 2,4,6‐trinitrobenzene sulfonic acid

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