pH and temperature dependence of glutamine uptake, carbon dioxide and ammonia production in kidney slices from acidotic rats.

George, Jose P.; Solomon, Sidney

doi:10.1113/jphysiol.1981.sp013785

Cited by 8 publications

(9 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a previous study (15), we have shown that the optimal OWH ratio shifts Significantly different from controls: *P < 0.005; **P < 0.01; ***P < 0.05. from 10 in animals of normal acid base balance down to 0.6 in acidosis for uptake of glutamine in rat kidney slices. At the optimum, uptake is also greater in the acidotic than normal (15). These results have been interpreted to indicate that chronic acidosis produces an adaptive membrane change which results in an increased permeability of glutamine at lower plasma pH.…”

mentioning

confidence: 74%

“…The number of animals used in each group are given in parentheses. The data for the 65-day-* Significantly different from nontreated controls (P < 0.05).old animals forTables I, 11, and 111 are taken from a previous publication(15).…”

mentioning

confidence: 99%

“…Preparation and incubation of kidney slices, measurement of glutamine uptake, CO, and NH3 production were described in detail previously (15,16). In short, four to six slices of kidney cortex, approximately 0.4-0.5 mm thickness, were cut from each kidney and placed in Warburg incubation flasks equipped with two side arms and a central well.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Effect of Acute and Chronic Acidosis on Glutamine Uptake in Kidney Slices of Newborn Rats

George

Solomon

1982

Experimental Biology and Medicine

View full text Add to dashboard Cite

Developmental changes in glutamine uptake, CO, and NH3 production was studied in kidney slices isolated from 12-, 18-, and 65-day-old rats under normal and acidotic conditions. The kidney slices from 12-and 18-day-old animals showed lower uptake of glutamine, CO, and NH3 production compared to 65-day-old animals. Chronic acidosis increased the ability of kidneys from postnatal rats to accumulate and metabolize glutamine but this increment was lower than the adults. Acute acidosis of newborn animals failed to show any significant changes in glutamine uptake and metabolism even though the degree of acidosis reached was the same between chronic and acute acidotic groups. Newborns failed to show an optimal pH for glutamine uptake and metabolism under normal and acidotic conditions. Along with other factors, the inability of newborn kidneys to increase transport of glutamine during an acid challenge can also explain the lowered ammonia production of newborn rats. 149

show abstract

mentioning

confidence: 74%

mentioning

confidence: 99%

See 1 more Smart Citation

Effect of Acute and Chronic Acidosis on Glutamine Uptake in Kidney Slices of Newborn Rats

George

Solomon

1982

Experimental Biology and Medicine

View full text Add to dashboard Cite

show abstract

“…This process is adequate for the complete leaching of ions out of very small tissue samples (cf. Law, 1975a;George & Solomon, 1981). Ion contents of leachates were estimated using the methods described below.…”

Section: Methodsmentioning

confidence: 99%

Characteristics of ionic binding by rat renal tissue in vitro.

Law¹

1984

The Journal of Physiology

View full text Add to dashboard Cite

4. In cortical slices in media containing equimolar Cl-and other monovalent anions, binding occurred according to the sequence acetate < salicylate < Cl-< SCN-; Cl-was completely displaced by P043-.5. When medium pH was lowered, Na+ binding was markedly reduced in both regions, whereas C1-binding increased (and became significant in outer medulla).6. In NaCl solutions, Na+ binding capacity was saturated at control Na+ concentrations. When [Na+] was progressively reduced (iso-osmolality being maintained by addition ofurea), bound Na+ in both regions was nearly linearly related to log medium [Na+].7. Raising medium osmolality with urea caused decreased Na+ binding and increased Cl-binding in both regions.8. Na+ binding in both regions was significantly reduced by pre-treatment with chondroitinase ABC.9. Binding of both ions was independent of temperature within the range 2-37°C.10. The possibility is raised that renal ionic binding might influence vectorial ion transport by affecting free ion activity in the region of the transporting cells.

show abstract

“…The study of this process is important to the understanding of transport events influenced by the availability of carbon dioxide. Most studies of metabolism of the carbon skeleton of glutamine have been per formed with either heterogeneous renal slices and subcellular organelles [6][7][8][9] or partially purified tubular preparations [10][11][12]. These methods do not lend themselves readily to an examination of segment-specific regulation.…”

mentioning

confidence: 99%

Tubular CO<sub>2</sub> Production from Glutamine in the Rat: Segmental Profile and Modulation

Mujais¹,

Zahid²

1992

Kidney Blood Press Res

View full text Add to dashboard Cite

The present study was designed to test whether tubular carbon dioxide production from the carbon skeleton of uniformly ¹⁴C-labelled glutamine exhibits quantitative and qualitative segmental heterogeneity. Our results show that CO₂ production from glutamine in the proximal convoluted tubule (PCT) was dependent on substrate concentrations and is saturable at 10^-4M of glutamine. Glutamine oxidation was demonstrable in all nephron segments examined. The PCT is the quantitatively predominant site of glutamine oxidation. Intermediate nephron segments, however, such as the thick ascending limb (MAL) and the distal convoluted tubule possess a significant capacity for glutamine oxidation, particularly when examined in terms of tubular protein content. Modulation of glutamine oxidation by extracellular pH was segment specific. Stimulation by acidosis and inhibition by alkalosis were observed in the PCT while carbon dioxide production from glutamine in the MAL was pH-insensitive. Glutamine oxidation was closely linked to sodium transport and greatly decreased by inhibition of Na-K-ATPase. In both the PCT and MAL, glutamine oxidation was inhibited by high extracellular potassium concentrations and in the PCT enhanced by extracellular hypokalemia. N-Ethyl maleiamide, an inhibitor of proton ATPase, led to almost complete cessation of CO₂ production from the substrate in both PCT and MAL. Acetazolamide, an inhibitor of carbonic anhydrase, led to a partial reduction in carbon dioxide formation in the PCT, but did not affect glutamine oxidation in the MAL. We conclude that segmental qualitative heterogeneity characterizes oxidation of the carbon skeleton of glutamine with proximal segments showing the predictable effects of pH changes and carbonic anhydrase inhibition. The MAL appears to be nonmodulating.

show abstract

pH and temperature dependence of glutamine uptake, carbon dioxide and ammonia production in kidney slices from acidotic rats.

Cited by 8 publications

References 28 publications

Effect of Acute and Chronic Acidosis on Glutamine Uptake in Kidney Slices of Newborn Rats

Effect of Acute and Chronic Acidosis on Glutamine Uptake in Kidney Slices of Newborn Rats

Characteristics of ionic binding by rat renal tissue in vitro.

Tubular CO<sub>2</sub> Production from Glutamine in the Rat: Segmental Profile and Modulation

Contact Info

Product

Resources

About