Sodium and Potassium Flux Rates in Normal Human Leucocytes in an Artificial Extracellular Fluid

1973 ◽  
Vol 44 (5) ◽  
pp. 439-445 ◽  
Author(s):  
P. J. Hilton ◽  
J. Patrick
Keyword(s):  
Extracellular Fluid ◽  
Dry Weight ◽  
Radioactive Isotopes ◽  
Efflux Rate ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
Potassium Flux ◽  
Normal Human ◽  
Potassium Influx ◽  
Sodium And Potassium

1. Sodium and potassium efflux and influx rates were studied in normal human leucocytes in an artificial extracellular fluid using radioactive isotopes. 2. The rate constant for sodium efflux was 4.2 h−1 corresponding to a sodium efflux rate of 487 mmol kg cell dry weight−1 h−1. Approximately three-quarters of this flux was ouabain sensitive. 3. Potassium influx was 346 mmol kg cell dry weight−1 h−1. Approximately two-thirds of the potassium influx was ouabain insensitive.

Sodium and Potassium Transport Rates in Normal Human Leucocytes in Hypo-Osmolal Extracellular Fluid

1974 ◽  
Vol 46 (5) ◽  
pp. 613-617 ◽  
Author(s):  
P. J. Hilton ◽  
J. Patrick
Keyword(s):  
Rate Constants ◽  
Extracellular Fluid ◽  
Dry Weight ◽  
Potassium Transport ◽  
Sodium Influx ◽  
Potassium Efflux ◽  
Normal Human ◽  
Potassium Influx ◽  
Sodium And Potassium

1. Sodium and potassium transport rates were studied in normal human leucocytes exposed to iso-osmolal and hypo-osmolal extracellular fluid. 2. Hypo-osmolality of the extracellular fluid led to an increase in sodium influx and a decrease in potassium influx expressed as mmol h−1 kg−1 cell dry weight. The fall in potassium influx was smaller than the rise in sodium influx and was confined to the ouabain-insensitive portion of the flux. 3. The rate constants for sodium and potassium efflux did not differ significantly between the iso-osmolal and hypo-osmolal media.

Effect of Extracellular Potassium on the Transport of Sodium and Potassium in Rat Thymocytes

1981 ◽  
Vol 61 (3) ◽  
pp. 307-312 ◽  
Author(s):  
R. B. Jones ◽  
J. Patrick ◽  
P. J. Hilton
Keyword(s):  
Potassium Concentration ◽  
Extracellular Potassium ◽  
Sodium Influx ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
Extracellular Potassium Concentration ◽  
External Potassium ◽  
Potassium Influx ◽  
Sodium And Potassium

1. The effect of extracellular potassium on the transport of sodium and potassium in rat thymocytes has been studied in vitro. 2. A significant increase in the rate constant for total and ouabain-sensitive sodium efflux was demonstrated at an extracellular potassium concentration of 1 mmol/l as compared with that at either 0 or 2 mmol/l. 3. At potassium concentrations below 3 mmol/l ouabain-sensitive sodium influx was observed suggesting sodium-sodium exchange catalysed by the sodium pump. 4. Both total and ouabain-insensitive potassium efflux rose with external potassium. A small ouabain-sensitive potassium efflux was observed at all levels of external potassium studied. 5. Total and ouabain-insensitive potassium influx increased with external potassium, but did not appear to saturate. Ouabain-sensitive potassium influx reached a maximum at an external potassium concentration of 2 mmol/l then decreased with increasing external potassium.

Frusemide-Sensitive Sodium and Potassium Transport by Human Leucocytes

1985 ◽  
Vol 68 (1) ◽  
pp. 89-91 ◽  
Author(s):  
Valerie E. Johnson ◽  
P. J. Hilton
Keyword(s):  
Potassium Transport ◽  
Sodium Influx ◽  
Potassium Efflux ◽  
Sodium Potassium ◽  
External Potassium ◽  
Normal Human ◽  
Potassium Influx ◽  
Net Flux ◽  
Sodium And Potassium

1. Frusemide-sensitive sodium and potassium transport by normal human leucocytes has been studied in vitro by both isotopic and net flux techniques. 2. In physiological media the leucocyte exhibits a frusemide-sensitive influx of sodium and potassium of equal magnitude compatible with a 1:1 co-transport system. 3. Cells exposed to zero external sodium and potassium (osmolality maintained with choline) demonstrated a frusemide-sensitive sodium and potassium efflux. 4. Frusemide-sensitive potassium influx was dependent on the presence of external sodium but frusemide-sensitive sodium influx persisted unchanged in the absence of external potassium. 5. Frusemide-sensitive potassium influx was dependent on external chloride but frusemide-sensitive sodium influx was chloride-independent. 6. These last two observations make it likely that the frusemide-sensitive pathway is capable of operating in modes other than sodium-potassium co-transport.

Na+ transport properties of the peritubular membrane of cortical collecting tubule

1982 ◽  
Vol 242 (6) ◽  
pp. F664-F671 ◽  
Author(s):  
E. Natke ◽  
L. C. Stoner
Keyword(s):  
Efflux Rate ◽  
Bathing Medium ◽  
Sodium Efflux ◽  
Collecting Tubule ◽  
Potassium Influx ◽  
Collecting Tubules ◽  
Low K ◽  
Sodium And Potassium ◽  
Cortical Collecting Tubule

The effects of varying endogenous aldosterone levels on the passive and active properties of the peritubular membrane were studied. Rabbits that were fed either a low Na+ (normal K+) diet or a high Na+, low K+ diet increased or decreased plasma aldosterone, respectively. Tubules were dissected, filled with oil, and incubated in 0 K+ medium to increase intracellular sodium. Cellular sodium and potassium content was measured by helium-glow photometry. The degree to which cells accumulate sodium and lose potassium is a function not only of time of exposure but also of diet. Tubules from animals on a low Na+ diet are about 6 times more permeable to sodium than those from animals fed a high Na+ diet. When tubules were loaded with sodium and returned to a normal (5 mM K+) bathing medium, net sodium efflux and potassium influx occurred. The rate of sodium efflux by cortical collecting tubules dissected from animals on the low Na+ diet was 2.3 times greater than the efflux rate of tubules from animals on the high Na+ diet. These data suggest that high levels of endogenous aldosterone enhance sodium transport measured in vitro across the peritubular membrane of cortical collecting tubule.

The Effect of External Potassium Concentration on Leucocyte Cation Transport in Vitro

1975 ◽  
Vol 49 (5) ◽  
pp. 385-390
Author(s):  
P. J. Hilton ◽  
R. P. S. Edmondson ◽  
R. D. Thomas ◽  
J. Patrick
Keyword(s):  
Potassium Concentration ◽  
Potassium Transport ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
Maximum Value ◽  
External Potassium ◽  
Potassium Influx ◽  
Potassium Exchange ◽  
Sodium And Potassium

1. Sodium and potassium transport rates in human leucocytes were measured in vitro at different external potassium concentrations. 2. At nominally zero external potassium concentrations, the ouabain-sensitive sodium efflux was reduced to less than 20% of its maximum value. There was evidence that under these conditions a ouabain-sensitive sodium-sodium exchange occurs. 3. Both total and ouabain-insensitive potassium influx increased with increasing external potassium concentration. The ouabain-sensitive potassium influx showed saturation. 4. Ouabain-insensitive potassium efflux was also stimulated by increasing the external potassium concentration, suggesting significant potassium-potassium exchange at physiological external potassium concentrations.

Electrophysiological analysis of potassium and sodium movements in crustacean nervous system

1975 ◽  
Vol 63 (1) ◽  
pp. 85-115
Author(s):  
N. J. Abbott ◽  
R. B. Moreton ◽  
Y. Pichon
Keyword(s):  
Nervous System ◽  
Peripheral Nerve ◽  
Model System ◽  
Diffusion Barriers ◽  
Ion Pump ◽  
Half Time ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
Electrophysiological Method ◽  
Sodium And Potassium

1. An electrophysiological method was used to estimate the half-times for sodium and potassium entry to, and efflux from, the extra-axonal space in peripheral nerve and central nervous connectives of two species of crustacean. Results from crab (marine) and crayfish (fresh water) were qualitatively similar. 2. Peripheral nerve showed no evidence for diffusion barriers, potassium entry and efflux being rapid, and proceeding at comparable rates. 3. In connective, potassium entry was extremely slow, with a half-time greater than 100 min, while potassium efflux was relatively rapid (T 1/2 = 6 min). Sodium movements were less restricted, but sodium entry was more rapid than sodium efflux. 4. The potassium experiments were compared with the behaviour of a theoretical model system. Evidence is presented for diffusional restriction to potassium at the connective perineurial layer. The mechanism of restriction may involve changes in permeability or activation of an ion pump in the perineurial layer. 5. The physiological significance of these findings is discussed.

Ion flux and Na+,K+-ATPase activity of erythrocytes and leucocytes in thyroid disease

1987 ◽  
Vol 72 (2) ◽  
pp. 171-179 ◽  
Author(s):  
F. A. Khan ◽  
D. N. Baron
Keyword(s):  
Atpase Activity ◽  
Thyroid Disease ◽  
Binding Capacity ◽  
Disease Status ◽  
Plasma Potassium ◽  
Sodium Concentration ◽  
Thyroid Stimulating Hormone ◽  
Efflux Rate ◽  
Sodium Efflux ◽  
Sodium And Potassium

1. In hyperthyroidism, erythrocytes show decreased Na+,K+-ATPase activity, decreased [3H]ouabain binding capacity (an index of the number of sodium pumps) and decreased active sodium and potassium flux rates, with a high intracellular sodium concentration. 2. As erythrocytes are non-nucleated and atypical cells, we have studied electrolyte status in thyroid disease using mixed leucocytes as well; the results obtained differed from those in erythrocytes. 3. When compared with findings in healthy subjects, leucocyte Na+,K+-ATPase activity, [3H]-oubain binding capacity, total and active rubidium (used instead of potassium) influx were all significantly increased in untreated hyperthyroidism and decreased in untreated hypothyroidism. 4. In hyperthyroidism, there was also a decrease in plasma potassium, an increase in sodium efflux rate and efflux rate constant, but no significant changes in cell sodium and potassium concentrations. All these changes returned to normal in successfully treated patients. There was a significant correlation between these abnormalities of electrolyte status and thyroid disease status (as serum thyroid stimulating hormone and free thyroxine).

scholarly journals Strophanthidin-Sensitive Components of Potassium and Sodium Movements in Skeletal Muscle As Influenced by the Internal Sodium Concentration

1968 ◽  
Vol 52 (3) ◽  
pp. 389-407 ◽  
Author(s):  
R. A. Sjodin ◽  
L. A. Beaugé
Keyword(s):  
Sodium Concentration ◽  
Ringer Solution ◽  
Intracellular Sodium ◽  
Sodium Ions ◽  
Potassium Efflux ◽  
Sodium Efflux ◽  
High Sodium ◽  
Ringer’S Solution ◽  
Low Sodium ◽  
Potassium Influx

"Low sodium" muscles were prepared which contained around 5 mmoles/kg fiber of intracellular sodium. "High sodium" muscles containing between 15 and 30 mmoles/kg fiber of intracellular sodium were also prepared. In low sodium muscles application of 10-5 M strophanthidin reduced potassium influx by about 5%. Potassium efflux was unaffected by strophanthidin under these conditions. In high sodium muscles, 10-5 M strophanthidin reduced potassium influx by 45% and increased potassium efflux by 70%, on the average. In low sodium muscles sodium efflux was reduced by 25% during application of 10-5 M strophanthidin while in high sodium muscles similarly treated, sodium efflux was reduced by about 60%. Low sodium muscles showed a large reduction in sodium efflux when sodium ions in the Ringer solution were replaced by lithium ions. The average reduction in sodium efflux was 4.5-fold. Of the amount of sodium efflux remaining in lithium. Ringer's solution, 40% could be inhibited by application of 10-5 M strophanthidin. The total sodium efflux from low sodium muscles exposed to Ringer's solution in which lithium had been substituted for sodium ions for a period of 1 hr can be fractionated as 78% Na-for-Na interchange, 10% strophanthidin-sensitive sodium pump, and 12% residual sodium efflux. It is concluded that large strophanthidin-sensitive components of sodium and potassium flux can be expected only at elevated sodium concentrations within the muscle cells.

Inhibition of Na(+)-K(+)-ATPase activates Na(+)-K(+)-2Cl- cotransporter activity in cultured ciliary epithelium

1994 ◽  
Vol 266 (1) ◽  
pp. C198-C205 ◽  
Author(s):  
J. Dong ◽  
N. A. Delamere ◽  
M. Coca-Prados
Keyword(s):  
Ciliary Epithelium ◽  
Channel Blockers ◽  
Efflux Rate ◽  
Potassium Efflux ◽  
Potassium Channel Blockers ◽  
A Cell ◽  
Potassium Influx ◽  
Atpase Inhibition ◽  
Total Potassium ◽  
Nonpigmented Ciliary Epithelium

Inhibition of Na(+)-K(+)-ATPase activates Na(+)-K(+)-2Cl- cotransporter activity in cultured ciliary epithelium. Am. J. Physiol. 266 (Cell Physiol. 35): C198-C205, 1994.--86Rb uptake experiments were conducted to measure Na(+)-K(+)-ATPase activity and Na(+)-K(+)-2Cl- cotransporter activity in a cell line derived from rabbit nonpigmented ciliary epithelium. The presence of a Na(+)-K(+)-2Cl- cotransporter was supported by the observation of a bumetanide-sensitive 86Rb uptake component that was dependent on the extracellular concentration of both sodium and chloride. Potassium influx mediated by the Na(+)-K(+)-2Cl- cotransporter and Na(+)-K(+)-ATPase accounted for approximately 46 and 33% of total potassium uptake, respectively, whereas both ouabain- and bumetanide-resistant uptake accounted for 9%. Inhibition of the Na(+)-K(+)-ATPase had a stimulatory effect on Na(+)-K(+)-2Cl- cotransporter activity, which was dependent on the extent and duration of Na(+)-K(+)-ATPase inhibition. Ouabain treatment stimulated the potassium (86Rb) efflux rate and reduced intracellular potassium ([K]i). Potassium channel blockers suppressed the ouabain-activated potassium efflux and inhibited the ouabain-induced activation of the Na(+)-K(+)-2Cl- cotransporter. We conclude that Na(+)-K(+)-ATPase inhibition leads to the opening of potassium channels, which exacerbates the depletion of cellular potassium; Na(+)-K(+)-2Cl- cotransporter stimulation caused by the fall of [K]i overrides the tendency of increased cellular sodium to inhibit the cotransporter.

Sodium and potassium flux of separated renal tubules

1964 ◽  
Vol 206 (3) ◽  
pp. 483-491 ◽  
Author(s):  
Maurice B. Burg ◽  
Evelyn F. Grollman ◽  
Jack Orloff
Keyword(s):  
Renal Cortex ◽  
Renal Tubule ◽  
Renal Tubules ◽  
Efflux Rate ◽  
Active Efflux ◽  
Potassium Flux ◽  
Efflux Rate Constant ◽  
K Transport ◽  
Sodium And Potassium ◽  
Cortical Slices

The Na and K fluxes of renal tubule cells were measured using suspensions of tubules separated from rabbit renal cortex. Kinetic analysis indicates that there are at least two Na compartments and two K compartments in the tubules. The rates at which Na and K exchanged were considerably greater than in renal cortical slices in accordance with predictions based on considerations of the geometrical arrangement of the cells in slices. Digitalis-like steroids, known to depress active cation transport, lowered the efflux rate constant for Na from the major Na compartment and diminished both K influx and the K efflux rate constants. The calculated active efflux of Na greatly exceeded the influx of K, indicating that active Na and K transport are not coupled in a 1:1 ratio.

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