scholarly journals Antibody-Induced Alterations in the Kinetic Characteristics of the Na:K Pump in Goat Red Blood Cells

1974 ◽  
Vol 63 (4) ◽  
pp. 389-414 ◽  
Author(s):  
John R. Sachs ◽  
J. Clive Ellory ◽  
Donna L. Kropp ◽  
Philip B. Dunham ◽  
Joseph F. Hoffman
Keyword(s):  
Red Blood Cells ◽  
Outer Surface ◽  
Blood Cells ◽  
Red Cells ◽  
Kinetic Characteristics ◽  
High Potassium ◽  
Low Concentrations ◽  
Pump Rate ◽  
Inner Surface ◽  
Low Potassium

The kinetic characteristics of the Na:K pump in high potassium (HK) and low potassium (LK) goat red cells were investigated after altering the intracellular cation concentrations. At low concentrations of intracellular K (Kc), increasing Kc at first stimulates the active K influx in HK cells, but at higher Kc the pump is inhibited. These results suggest that in HK cells Kc acts both at a stimulatory site at the inner aspect of the pump and by competition with intracellular Na (Nac) at the Na translocation sites. In LK cells, Kc inhibits the active K influx and the sensitivity of LK cells to inhibition is much greater than the sensitivity of HK cells. Exposure of LK cells to an antibody (anti-L), raised in an HK sheep by injection of LK sheep cells, increased the active K influx at any given Kc. The effect of the antibody was greater at higher intracellular K concentrations, and in cells with very low concentrations of K the antibody had little effect on the pump rate. The failure of anti-L to stimulate the pump in low Kc LK cells was not due to failure of the antibody to bind to the cells. Anti-L combining at the outer surface of the cell reduces the affinity of the pump at the inner surface for K at the inhibitory sites. The maximal pump rate in LK cells at optimal Na and K concentrations is less than the maximal pump rate of HK cells under the same circumstances.

scholarly journals Interaction of HK and LK Goat Red Blood Cells with Ouabain

1974 ◽  
Vol 64 (5) ◽  
pp. 536-550 ◽  
Author(s):  
John R. Sachs ◽  
Philip B. Dunham ◽  
Donna L. Kropp ◽  
J. Clive Ellory ◽  
Joseph F. Hoffman
Keyword(s):  
Red Blood Cells ◽  
Binding Sites ◽  
Blood Cells ◽  
Red Cells ◽  
Ouabain Binding ◽  
High Potassium ◽  
Considerable Heterogeneity ◽  
Low Potassium ◽  
The Difference ◽  
Calculated Number

The characteristics of the interaction of Na-K pumps of high potassium (HK) and low potassium (LK) goat red blood cells with ouabain have been determined. The rate of inhibition by ouabain of the pump of HK cells is greater than the rate of inhibition of the pumps of LK cells. Treatment of LK cells with an antibody (anti-L) raised in HK sheep by injecting LK sheep red cells increases the rate of inhibition of the LK pumps by ouabain to that characteristic of HK pumps; reduction of intracellular K (Kc) in LK cells increases the rate at which ouabain inhibits their pumps and exposure of these low Kc cells to anti-L does not affect the rate of inhibition. There is considerable heterogeneity in the pumps of both HK and LK cells in the rate at which they interact with ouabain or the rate at which they pump or both. LK pumps which are sensitive to stimulation by anti-L bind ouabain less rapidly than the remainder of the LK pumps and exposure to antibody increases the rate at which ouabain binds to the sensitive pumps; the difference between the two types of pumps disappears if intracellular K is very low. The calculated number of ouabain molecules bound at 100% inhibition of the pump is about the same for HK and LK cells. Although exposure to anti-L increases the apparent number of ouabain binding sites in LK cells at normal Kc, it does not alter the apparent number of sites in LK cells when Kc has been reduced.

scholarly journals Active Sodium and Potassium Transport in High Potassium and Low Potassium Sheep Red Cells

1971 ◽  
Vol 58 (4) ◽  
pp. 438-466 ◽  
Author(s):  
P. G. Hoffman ◽  
D. C. Tosteson
Keyword(s):  
Cell Types ◽  
Red Cells ◽  
Kinetic Characteristics ◽  
High Potassium ◽  
Cation Composition ◽  
Sheep Red Cells ◽  
Pump Rate ◽  
Low Potassium ◽  
K Transport ◽  
External K

The kinetic characteristics of the ouabain-sensitive (Na + K) transport system (pump) of high potassium (HK) and low potassium (LK) sheep red cells have been investigated. In sodium medium, the curve relating pump rate to external K is sigmoid with half maximal stimulation (K1/2) occurring at 3 mM for both cell types, the maximum pump rate in HK cells being about four times that in LK cells. In sodium-free media, both HK and LK pumps are adequately described by the Michaelis-Menten equation, but the K1/2 for HK cells is 0.6 ± 0.1 mM K, while that for LK is 0.2 ± 0.05 mM K. When the internal Na and K content of the cells was varied by the PCMBS method, it was found that the pump rate of HK cells showed a gradual increase from zero at very low internal Na to a maximum when internal K was reduced to nearly zero (100% Na). In LK cells, on the other hand, no pump activity was detected if Na constituted less than 70% of the total (Na + K) in the cell. Increasing Na from 70 to nearly 100% of the internal cation composition, however, resulted in an exponential increase in pump rate in these cells to about ⅙ the maximum rate observed in HK cells. While changes in internal composition altered the pump rate at saturating concentrations of external K, it had no effect on the apparent affinity of the pumps for external K. These results lead us to conclude that the individual pump sites in the HK and LK sheep red cell membranes must be different. Moreover, we believe that these data contribute significantly to defining the types of mechanism which can account for the kinetic characteristics of (Na + K) transport in sheep red cells and perhaps in other systems.

Changes in the cation composition and active K+ transport in the red cells of fetal sheep prepartum

1985 ◽  
Vol 63 (11) ◽  
pp. 1454-1459
Author(s):  
M. W. Wolowyk ◽  
J. C. Ellory
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Sodium Pump ◽  
Red Cells ◽  
Ouabain Binding ◽  
High Potassium ◽  
Fetal Sheep ◽  
Sodium Pumps ◽  
Low Potassium ◽  
Pump Activity

The red blood cells of lambs, genotypically low potassium type, undergo a transition from high potassium to low potassium cell type from parturition onwards. This involves gradual changes in cell ion content, sodium pump activity, and ouabain binding. In the present study we investigated the properties of fetal red blood cells from 30 days prepartum using the chronically cannulated pregnant ewe preparation. We demonstrate that intracellular sodium increases and potassium decreases from −30 days onwards. Sodium pump activity monitored either by tracer potassium influx or ouabain binding is markedly higher in the early fetal samples examined and declines fourfold during the final month in utero. Unlike the maternal low potassium cells the early fetal red cells are refractory in terms of sodium pump stimulation by anti-L, the antibody in fact consistently inhibiting the pump. Finally, we have investigated the volume sensitivity and development of the ouabain-insensitive potassium fluxes in these cells and found that both fetal and maternal cells show a marked chloride-dependent, volume-sensitive passive potassium flux. We conclude that the decrease in active sodium transport between fetal red cells and adult low potassium cells is achieved partly by a reduction in the density of sodium pumps per cell, and then later by the introduction into the circulation of cells with Lp-antigen-modified sodium pumps.

scholarly journals The Effect of 2,4,6-Trinitro-m-Cresol on Cation and Anion Transport in Sheep Red Blood Cells

1971 ◽  
Vol 57 (5) ◽  
pp. 593-609 ◽  
Author(s):  
Robert B. Gunn ◽  
Daniel C. Tosteson
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Room Temperature ◽  
Anion Transport ◽  
Red Cells ◽  
High Potassium ◽  
Sheep Red Blood Cells ◽  
Low Potassium ◽  
Potassium Influx ◽  
Stimulation Of

2,4,6-Trinitro-3-methyl-phenol (trinitrocresol, H+TNC-) was found to inhibit anion and stimulate cation movements across the membranes of both high potassium (HK) and low potassium (LK) sheep red blood cells. The concentration of TNC- required to inhibit SO4- and Cl- efflux (10-5-10-3 M) was less than that required to increase Na+ and K+ leakage (10-3-10-2 M). Both the inhibition of anion and stimulation of cation permeation were reversed if TNC- was washed from the red cells. The cation leak caused by TNC- was much greater at 0° and 37°C than at room temperature (23°C). In sheep red cells, TNC- was found to be about 20 times more effective than salicylate and about 40 times more effective than thiocyanate in increasing cation leak. TNC- also inhibited the ouabain-sensitive potassium influx.

Voltage-activated cation permeability in high-potassium but not low-potassium red blood cells

1990 ◽  
Vol 258 (6) ◽  
pp. C1169-C1172 ◽  
Author(s):  
J. A. Halperin ◽  
C. Brugnara ◽  
T. Van Ha ◽  
D. C. Tosteson
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Dielectric Breakdown ◽  
Cation Transport ◽  
Membrane Component ◽  
Transport Pathway ◽  
High Potassium ◽  
Human Red Blood Cells ◽  
Cation Permeability ◽  
Low Potassium

We have recently reported that voltage-activated fluxes of Na, K, and Ca occur in human red blood cells [J.A. Halperin, C. Brugnara, M. Tosteson, T. Van Ha, and D. C. Tosteson. Am. J. Physiol. 257 (Cell Physiol. 26): C986-C996, 1989]. The cation permeability increases progressively as the membrane potential becomes more inside positive above +20 mV. In this paper we show that this effect also occurs in high-potassium (HK), but not in low-potassium (LK), sheep and dog red blood cells. This result suggests that the voltage-activated cation transport pathway is not the result of nonspecific dielectric breakdown of the lipid bilayer but, rather, relates to some membrane component, presumably a protein, that is expressed in HK human and sheep but not in LK sheep and dog red blood cells.

Electron probe microanalysis of red blood cells. I. Methods and evaluation

1978 ◽  
Vol 235 (5) ◽  
pp. C245-C250 ◽  
Author(s):  
R. G. Kirk ◽  
C. Bronner ◽  
W. Barba ◽  
D. C. Tosteson
Keyword(s):  
Red Blood Cells ◽  
Electron Probe Microanalysis ◽  
Blood Cells ◽  
Electron Probe ◽  
Freeze Drying ◽  
Pyrolytic Graphite ◽  
High Potassium ◽  
Spray Technique ◽  
Low Potassium ◽  
Cell Volumes

The concentrations of potassium, sodium, and iron in human and sheep red blood cells were measured with an electron probe. Cells were prepared for analysis by spraying them on pyrolytic graphite supports. The results obtainedwith this spray technique agreed well with values measured on similar cells that were prepared for analysis by freezing, sectioning, and freeze-drying. Higher Na concentrations and lower K concentrations were found to be associated with lower cell volumes in human and high-potassium sheep cells. In low-potassium sheep cells the reverse was found, lower Na and higher K concentrations were associated with lower cell volumes. However, the amounts of iron were found to remain relatively constant in all human cells.

scholarly journals Interaction of Mercury with Human Erythrocytes

1962 ◽  
Vol 45 (3) ◽  
pp. 395-410 ◽  
Author(s):  
R. Weed ◽  
J. Eber ◽  
A. Rothstein
Keyword(s):  
Red Blood Cells ◽  
Glucose Uptake ◽  
Binding Sites ◽  
Blood Cells ◽  
Reduced Glutathione ◽  
Osmotic Fragility ◽  
Red Cells ◽  
Sulfhydryl Groups ◽  
Low Concentrations ◽  
Binding Curves

The binding of mercury to red blood cells was measured in terms of Hg203 uptake and desorption. The significant features of the binding are: (a) rapid achievement of equilibrium (3 to 5 minutes); (b) release of a Hg-complexing material from the red cells themselves which distorts the binding curves at low concentrations of metal (2.5 x 10-7 to 5.0 x 10-6 M); (c) prevention of binding by cysteine, glutathione, penicillamine, and EDTA but not by imidazole or histidine; (d) binding of mercury in amounts up to 7 times the reduced glutathione concentration of the cells before combination with glutathione itself; (e) binding primarily to sulfhydryl groups of hemoglobin and to a small number of stromal sulfhydryl groups, but also to other non-sulfhydryl cellular ligands after saturation of the sulfhydryl groups. Associated with the binding is inhibition of glucose uptake, induction of loss of K+, and decrease in osmotic fragility. These effects increase over the range of concentrations (1 x 10-17 to 1 x 10-15 moles of Hg/RBC) well below those that result in saturation of the cellular binding sites; above 1 x 10-15 moles/RBC, the effects decrease as the cells become saturated.

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