Comparison of glutamate metabolism in low K (LK), high K and high glutathione (HK/HG) and high K and low glutathione (HK/LG) dog red blood cells

1998 ◽  
Vol 8 (3) ◽  
pp. 159-165 ◽  
Author(s):  
H. Ochiai ◽  
K. Higa ◽  
H. Fujise
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Glutamate Metabolism ◽  
High K ◽  
Low K

Kinetics of Na-Li exchange in high and low K sheep red blood cells

1989 ◽  
Vol 257 (1) ◽  
pp. C58-C64 ◽  
Author(s):  
K. H. Ryu ◽  
N. C. Adragna ◽  
P. K. Lauf
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Cell Types ◽  
Sheep Red Blood Cells ◽  
High K ◽  
Ping Pong ◽  
Order Of Magnitude ◽  
Low K ◽  
Kinetics Of ◽  
System Operating

The kinetic parameters and transport mechanism of Na-Li exchange were studied in both low K (LK) and high K (HK) sheep red blood cells with cellular Na [( Na]i) and Li concentrations [( Li]i) adjusted by the nystatin technique (Nature New Biol. 244: 47-49, 1973 and J. Physiol. Lond. 283: 177-196, 1978). Maximum velocities (Vm) for Li fluxes and half-activation constants (K1/2) for Li and Na of the Na-Li exchanger were determined. The K1/2 values for both Li and Na appeared to be similar in both cell types, although they were about two to three times lower on the inside than on the outside of the membrane. Furthermore, the K1/2 values for Li were at least an order of magnitude smaller than those for Na, suggesting substantial affinity differences for these two cations. The Vm values for Li fluxes, on the other hand, appear to be lower in HK than in LK cells. When Na and Li fluxes were measured simultaneously, a trans stimulatory effect by Na on Li fluxes was observed. From measurements of Li influx at different concentrations of external Li and different [Na]i, the ratio of the apparent Vm to the apparent external Li affinity was calculated to be independent of [Na]i for both types of sheep red blood cells. Similar trans effects of external Na were observed on Li efflux at varying [Li]i. These results are expected for a system operating by a “ping-pong” mechanism.

Differentiation of Na(+)-K+ pumps of low-K+ sheep red blood cells is promoted by Lp membrane antigens

1993 ◽  
Vol 265 (1) ◽  
pp. C99-C105 ◽  
Author(s):  
Z. C. Xu ◽  
P. B. Dunham ◽  
B. Dyer ◽  
R. Blostein
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Rat Kidney ◽  
Striking Increase ◽  
Sheep Red Blood Cells ◽  
High K ◽  
Membrane Antigens ◽  
Low K ◽  
Kinetics Of

Na(+)-K+ pumps of red blood cells from sheep of the low-K+ (LK) phenotype undergo differentiation during circulation, manifested in part by a striking increase in sensitivity to inhibition by intracellular K+ (Ki). Pumps of red blood cells from sheep from the allelic phenotype, high K+ (HK), do not undergo this type of maturation. The hypothesis was tested that the Lp antigen, found on LK but not HK cells, is responsible for the maturation of LK pumps. Lp antigens have been shown to inhibit LK pumps because anti-Lp antibody stimulates the pumps by relieving inhibition by the antigen. Lp antigens were recently shown to be molecular entities separate from Na(+)-K+ pumps [Xu, Z.-C., P. Dunham, J. Munzer, J. Silvius, and R. Blostein. Am. J. Physiol. 263 (Cell Physiol. 32): C1007-C1014, 1992]. The test of the hypothesis was to modify the Lp antigens of immature LK red blood cells with two kinds of treatments, anti-Lp antibody and trypsinization (which cleaves Lp), and to observe the effects of these treatments on maturation of pumps during culture of the cells in vitro. Both of these treatments prevented the maturation of the kinetics of the pumps to the Ki-sensitive pattern, supporting the hypothesis that interaction of the pumps with Lp antigens is responsible for the maturation of the pumps. Strong supportive evidence came from experiments on Na(+)-K+ pumps from rat kidney delivered into immature LK sheep red blood cells by microsome fusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Volume and anion dependency of ouabain-resistant K-Rb fluxes in sheep red blood cells

1988 ◽  
Vol 255 (3) ◽  
pp. C331-C339 ◽  
Author(s):  
P. K. Lauf
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Cell Types ◽  
Sheep Red Blood Cells ◽  
K Cells ◽  
High K ◽  
Before And After ◽  
Volume Response ◽  
Altered Cell ◽  
Low K

The effect of six different anions on the volume response of ouabain-resistant K transport was systematically studied at extracellular pH (pHo) = 7.4 in sheep red blood cells of both low and high K genotype before and after treatment with the sulfhydryl (SH) reagent N-ethylmaleimide (NEM). In methanesulfonate (CH3SO3), both the apparent Rb permeability (P(app)Rb), calculated from ouabain-resistant Rb influx), and K permeability (PK, calculated from the rate constants of ouabain-resistant zero-trans K efflux, 0k(OR)K) were volume independent and close to 10(-10) cm/s for both cell types, but in Cl, Br, I, SCN, and NO3 they were significantly different in low and high K cells with altered cell volumes. Thus, in 15% osmotically shrunken low K cells, P(app)Rb) and PK were similar regardless of the anions present, but upon 10-15% swelling, they increased to approximately 4-6 X 10(-9) cm/s in Br and 2 X 10(-9) cm/s in Cl and also increased with comparatively small increments in I, SCN, and NO3. Treatment with NEM enhanced both P(app)Rb) and PK, particularly in shrunken low K cells, to approximately 10(-8) cm/s in Br and Cl but not in I, SCN, and NO3. In shrunken or isotonic high K cells, P(app)Rb) and PK were close to 10(-10) cm/s in all anions except for SCN. Swelling and/or NEM increased PK and P(app)Rb) in Cl and Br only two- to threefold.(ABSTRACT TRUNCATED AT 250 WORDS)

Decline in number of Na-K pumps on low-K+ sheep reticulocytes during maturation is modulated by Lp antigen

1994 ◽  
Vol 266 (5) ◽  
pp. C1173-C1181 ◽  
Author(s):  
Z. C. Xu ◽  
P. B. Dunham ◽  
B. Dyer ◽  
R. Blostein
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Blood Group Antigen ◽  
Cell Maturation ◽  
Alpha Subunit ◽  
Ouabain Binding ◽  
High K ◽  
Antigen System ◽  
Low K

The number of the Na-K pumps on sheep red blood cells declines markedly during cell maturation. In addition, in red blood cells of the low-K+ (LK) phenotype, there is an increase during maturation in the affinity of the pumps for intracellular K+. This increase does not occur in cells of the high-K+ (HK) phenotype. This HK/LK polymorphism is associated with the M/L blood group antigen system. The Lp antigen, which is on only LK cells, promotes the increase in affinity for K+ [Am. J. Physiol. 265 (Cell Physiol. 34): C99-C105, 1993]. Mature LK cells have fewer pumps than mature HK cells. The present study shows that the Lp antigen also promotes the loss of pumps in LK cells. The evidence was that modification of the Lp antigen of immature LK red blood cells either with anti-Lp antibody or by trypsinization diminished the loss of pumps during culture in vitro (numbers determined from [3H]ouabain binding). Confirmation came from demonstration of the decline during maturation of the amount of the alpha-subunit of the Na-K pump (measured by immunoblotting), which was also retarded by pretreatment with anti-Lp or trypsin. Comparisons of the relative amounts of Lp antigen on immature and mature LK cells showed that there is little decline in number of antigens during maturation. Therefore there is an increase in the antigen-to-pump ratio during maturation even though an association between pumps and antigens is necessary for the loss of pumps.

Several cation transporters and volume regulation in high-K dog red blood cells

1991 ◽  
Vol 260 (3) ◽  
pp. C589-C597 ◽  
Author(s):  
H. Fujise ◽  
I. Yamada ◽  
M. Masuda ◽  
Y. Miyazawa ◽  
E. Ogawa ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Volume Regulation ◽  
Cation Composition ◽  
Influx Rate ◽  
Physiological Conditions ◽  
High K ◽  
Dependent Transport ◽  
Low K ◽  
K Transport

Normal dog red blood cells lack the Na-K pump, and their cation composition is low K and high Na (LK). Recently, a dog was found with red blood cells containing high K and low Na concentrations (HK) due to the existence of the Na-K pump. In the present study, cation transport and volume regulation in HK cells were compared with those of LK cells. HK cells showed not only Rb influx through a Na-K pump, but also Rb influx through a Cl-dependent K transporter. The Rb influx rate through the Na-K pump was 0.65-1.44 mmol.l cells-1.h-1 in Cl and 1.75-2.24 mmol.l cells-1.h-1 in NO3, in HK cells, but only trace activities are found in LK cells. In HK cells, the Rb influx rate through Cl-dependent K transport was 0.36-0.96 mmol.l cells-1.h-1, and it was enhanced in swollen cells but vanished in shrunken cells. In LK cells, the transport was evident only in swollen cells. The original volume of swollen HK cells was restored by water extrusion promoted by Cl-dependent transport. The Na-Ca exchange transporter, which works as a volume regulator in LK cells, functioned in HK cells only when they were loaded with Na. Hence, the exchange transporter is latent in HK cells under physiological conditions. Moreover, the exchange transporter could restore the cell volume in swollen and Na-loaded HK cells. However, the volume in HK cells was still larger than that in LK cells, while the Na-Ca exchange transporter was working.(ABSTRACT TRUNCATED AT 250 WORDS)

Rat kidney Na-K pumps incorporated into low-K+ sheep red blood cell membranes are stimulated by anti-Lp antibody

1992 ◽  
Vol 263 (5) ◽  
pp. C1007-C1014 ◽  
Author(s):  
Z. C. Xu ◽  
P. B. Dunham ◽  
J. S. Munzer ◽  
J. R. Silvius ◽  
R. Blostein
Keyword(s):  
Blood Cell ◽  
Red Blood Cells ◽  
Red Blood Cell ◽  
Blood Cells ◽  
Rat Kidney ◽  
Molecular Entity ◽  
Sheep Red Blood Cells ◽  
K Cells ◽  
High K ◽  
Low K

A genetic dimorphism of sheep red blood cells characterized by differences in the intracellular K+ concentration of mature red blood cells (low-K+ or high-K+ cells) reflects differences in their Na-K pumps and is known to be linked to the ML blood group system. We investigated the relationship of Na-K pumps in red blood cells from sheep of the low-K+ phenotype with an antigen, Lp, that is restricted to low-K+ cells. Anti-Lp antibody stimulates the Na-K pumps in these cells presumably by relieving inhibition of the pumps by Lp. The questions addressed were as follows: is Lp a molecular entity distinct from pumps and, if so, can it interact with pumps of exogenous origin? Rat kidney Na-K pumps were incorporated by fusion of microsomes into either low-K+ or high-K+ sheep red blood cells. The activity of the exogenous kidney pumps was distinguished from that of the endogenous red blood cell pumps by the low sensitivity of rodent pumps to ouabain. Anti-Lp stimulated by > 50% rat kidney pumps incorporated into immature low-K+ sheep cells. This indicates that Lp is a distinct molecular entity free to dissociate from endogenous pumps and inhibit exogenous pumps. Anti-Lp did not stimulate kidney pumps incorporated into mature low-K+ cells but did stimulate kidney pumps following in vitro maturation of microsome fused reticulocytes, probably reflecting restriction of lateral movement of pumps and antigens by the cytoskeleton in mature cells.

Stimulation of Na+-K+ pump in sheep red blood cells by heteroimmune anti-sheep red cell antibodies

1984 ◽  
Vol 247 (1) ◽  
pp. C120-C123 ◽  
Author(s):  
P. B. Dunham ◽  
B. E. Farquharson ◽  
R. L. Bratcher
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Red Cell ◽  
Sheep Red Blood Cells ◽  
L Cells ◽  
High K ◽  
First Time ◽  
Low K ◽  
K Transport ◽  
Stimulation Of

In the HK-LK polymorphism of sheep red blood cells, alloimmune antiserum against the L antigen on LK cells is known to stimulate the Na+-K+ pump in low K+ (LK) cells, but alloimmune antiserum against the M antigen of high K+ (HK) cells does not. We have shown for the first time that heteroimmune antibodies against sheep red blood cells raised in mice can stimulate the pump. Heteroimmune antibodies against both LK(L) cells and HK(M) cells stimulated active K+ transport in LK cells. Furthermore heteroimmune antibodies against LK(L) cells also stimulated the pump in HK cells. As expected, alloimmune and heteroimmune antibodies acted at different sites in stimulating transport in LK cells.

Volume-dependent K+ transport in rabbit red blood cells comparison with oxygenated human SS cells

1989 ◽  
Vol 257 (1) ◽  
pp. C114-C121 ◽  
Author(s):  
N. al-Rohil ◽  
M. L. Jennings
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Cell Volume Regulation ◽  
Sulfhydryl Group ◽  
Cell Swelling ◽  
Inhibitory Potency ◽  
Ph Optimum ◽  
The Relationship ◽  
Low K ◽  
K Transport

In this study the volume-dependent or N-ethylmaleimide (NEM)-stimulated, ouabain-insensitive K+ influx and efflux were measured with the tracer 86Rb+ in rabbit red blood cells. The purpose of the work was to examine the rabbit as a potential model for cell volume regulation in human SS red blood cells and also to investigate the relationship between the NEM-reactive sulfhydryl group(s) and the signal by which cell swelling activates the transport. Ouabain-resistant K+ efflux and influx increase nearly threefold in cells swollen hypotonically by 15%. Pretreatment with 2 mM NEM stimulates efflux 5-fold and influx 10-fold (each measured in an isotonic medium). The ouabain-resistant K+ efflux was dependent on the major anion in the medium. The anion dependence of K+ efflux in swollen or NEM-stimulated cells was as follows: Br- greater than Cl- much greater than NO3- = acetate. The magnitudes of both the swelling- and the NEM-stimulated fluxes are much higher in young cells (density separated but excluding reticulocytes) than in older cells. Swelling- or NEM-stimulated K+ efflux in rabbit red blood cells was inhibited 50% by 1 mM furosemide, and the inhibitory potency of furosemide was enhanced by extracellular K+, as is known to be true for human AA and low-K+ sheep red blood cells. The swelling-stimulated flux in both rabbit and human SS cells has a pH optimum at approximately 7.4. We conclude that rabbit red blood cells are a good model for swelling-stimulated K+ transport in human SS cells.(ABSTRACT TRUNCATED AT 250 WORDS)

K(+)-Cl- cotransport and volume regulation in the light and the dense fraction of high-K+ dog red blood cells

1997 ◽  
Vol 273 (3) ◽  
pp. R991-R998 ◽  
Author(s):  
H. Fujise ◽  
K. Abe ◽  
M. Kamimura ◽  
H. Ochiai
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Divalent Cations ◽  
Regulatory Volume Decrease ◽  
Marker Enzyme ◽  
High K ◽  
Dense Fraction ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Volume Decrease ◽  
Light Cells

We examined a chloride (Cl-)-dependent K+ transport (K(+)-Cl- cotransport) and regulatory volume decrease in dog red blood cells with high K+, low Na+, and high glutathione (GSH) content (HK/HG) due to the presence of an Na(+)-K+ pump. The HK/HG cells were separated according to their density, and the age-marker enzyme activities, such as glucose-6-phosphate dehydrogenase and cholinesterase, were determined. Unexpectedly, we found that young cells were heavier (more dense) and smaller in size compared with the old cells, which were lighter (less dense) and larger. The K(+)-Cl- cotransport was nearly 10-fold higher in the most dense cells, representing a 12% fraction of the total population compared with the lightest cohort. Although K(+)-Cl- cotransport in both the dense and the light cells was activated by N-ethylmaleimide, swelling and depletion of cellular divalent cations and the activation of the transport in the dense cells was greater. Both the dense and light cells regulated their volume when they were isosmotically swollen. Therefore, the lower activity of K(+)-Cl- cotransport might not explain the relative large volume in old HK/HG cells. The concentration of GSH and glutamate was higher in the light cells. Thus the higher the GSH and glutamate concentration, the greater the cell volume and the lower the K(+)-Cl- cotransport.

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