Fixation and Fate of Bicarbonate in Glutamine Synthesis from Alanine in Guinea Pig Renal Cortex

2015 ◽  
pp. 96-100
Author(s):  
C. Michoudet ◽  
G. Martin ◽  
G. Baverel
Keyword(s):  
Guinea Pig ◽  
Renal Cortex ◽  
Glutamine Synthesis

scholarly journals Glutamine synthesis from aspartate in guinea-pig renal cortex

1990 ◽  
Vol 268 (2) ◽  
pp. 437-442 ◽  
Author(s):  
G Baverel ◽  
G Martin ◽  
C Michoudet
Keyword(s):  
Glutamine Synthetase ◽  
Guinea Pig ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Tricarboxylic Acid Cycle ◽  
Kidney Cortex ◽  
Carbon And Nitrogen ◽  
Ammonia Release ◽  
Glutamine Synthesis ◽  
Methionine Sulphoximine ◽  
Main Carbon

1. Glutamine was found to be the main carbon and nitrogen product of the metabolism of aspartate in isolated guinea-pig kidney-cortex tubules. Glutamate, ammonia and alanine were only minor products. 2. Carbon-balance calculations and the release of 14CO2 from [U-14C]aspartate indicate that oxidation of the aspartate carbon skeleton occurred. 3. A pathway involving aspartate aminotransferase, glutamate dehydrogenase, glutamine synthetase, phosphoenolpyruvate carboxykinase, pyruvate kinase, pyruvate dehydrogenase and enzymes of the tricarboxylic acid cycle is proposed for the conversion of aspartate into glutamine. 4. Evidence for this pathway was obtained by: (i) inhibiting aspartate removal by amino-oxyacetate, an inhibitor of transaminases, (ii) the use of methionine sulphoximine, an inhibitor of glutamine synthetase, which induced a large increase in ammonia release from aspartate, (iii) the use of quinolinate, an inhibitor of phosphoenolpyruvate carboxykinase, which inhibited glutamine synthesis from aspartate, (iv) the use of alpha-cyano-4-hydroxycinnamate, an inhibitor of the mitochondrial transport of pyruvate, which caused an accumulation of pyruvate from aspartate, and (v) the use of fluoroacetate, an inhibitor of aconitase, which inhibited glutamine synthesis with concomitant accumulation of citrate from aspartate.

scholarly journals Release and fixation of CO2 by guinea-pig kidney tubules metabolizing aspartate

1992 ◽  
Vol 284 (3) ◽  
pp. 697-703
Author(s):  
G Martin ◽  
C Michoudet ◽  
N Vincent ◽  
G Baverel
Keyword(s):  
Guinea Pig ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Co2 Fixation ◽  
Carbon Oxidation ◽  
Kidney Tubules ◽  
Pig Kidney ◽  
Glutamine Synthesis ◽  
Oxoglutarate Dehydrogenase

1. The metabolism of L-[U-14C]aspartate, L-[1-14C]aspartate and L-[4-14C]aspartate was studied in isolated guinea-pig kidney tubules. 2. Oxidation of C-1 plus that of C-4 of aspartate accounted for 90-92% of the CO2 released from aspartate, whereas oxidation of the inner carbon atoms of aspartate (which occurs beyond the 2-oxoglutarate dehydrogenase step) represented only 8-10% of aspartate carbon oxidation. 3. The formation of [1-14C]glutamine and [1-14C]glutamate from [1-14C]aspartate and [4-14C]aspartate indicated that about one-third of the oxaloacetate synthesized from aspartate underwent randomization at the level of fumarate. 4. With [U-14C]aspartate as substrate, the percentage of the C-1 of glutamate and glutamine found radiolabelled after 60 min of incubation was 92.7% and 47.5% in the absence and the presence of bicarbonate respectively. 5. That CO2 fixation occurred at high rates in the presence of bicarbonate was demonstrated by incubating tubules with aspartate plus [14C]bicarbonate; under this condition, the label fixed was found in C-1 of glutamate, glutamine and aspartate, as well as in C-4 of aspartate, demonstrating not only randomization of aspartate carbon but also aspartate resynthesis secondary to oxaloacetate cycling via phosphoenolpyruvate carboxykinase, pyruvate kinase and pyruvate carboxylase. 6. The importance of CO2 fixation in glutamine synthesis from aspartate is discussed in relation to the possible role of the guinea-pig kidney in systemic acid-base regulation in vivo.

Accumulation of uric acid by slices of kidney cortex

1961 ◽  
Vol 200 (2) ◽  
pp. 387-392 ◽  
Author(s):  
Margaret M. Platts ◽  
Gilbert H. Mudge
Keyword(s):  
Uric Acid ◽  
Guinea Pig ◽  
Renal Cortex ◽  
Renal Tubule ◽  
Cellular Mechanism ◽  
Kidney Cortex ◽  
Mongrel Dog ◽  
Bidirectional Transport ◽  
Methodological Problems

Accumulation of uric acid by surviving slices of renal cortex occurs by active transport. On the basis of substrate and inhibitor effects, the cellular mechanism has many features in common with that for p-aminohippurate accumulation. Uptake was most marked in the chicken, rabbit and guinea pig. Active accumulation could not be demonstrated for man, the mongrel dog or the rat. Agents that are uricosuric in man inhibited accumulation in the species studied. However, the bidirectional transport of uric acid across the renal tubule poses methodological problems that may not be completely resolved in in vitro studies.

scholarly journals Ontogeny of histone H1 in guinea pig renal cortex. 258

1997 ◽  
Vol 41 ◽  
pp. 45-45
Author(s):  
Edward N. Guillery ◽  
David J. Huss
Keyword(s):  
Guinea Pig ◽  
Renal Cortex ◽  
Histone H1

Pyruvate carboxylation in glutamine synthesis from alanine by isolated guinea-pig renal cortical tubules

1988 ◽  
Vol 412 (1-2) ◽  
pp. 7-11 ◽  
Author(s):  
Christian Michoudet ◽  
Guy Martin ◽  
Gabriel Baverel
Keyword(s):  
Guinea Pig ◽  
Pyruvate Carboxylation ◽  
Glutamine Synthesis

scholarly journals Glutamine synthesis from glucose and ammonium chloride by guinea-pig kidney tubules

1994 ◽  
Vol 297 (1) ◽  
pp. 69-74 ◽  
Author(s):  
C Michoudet ◽  
M F Chauvin ◽  
G Baverel
Keyword(s):  
Glucose Metabolism ◽  
Guinea Pig ◽  
Carbon Skeleton ◽  
Kidney Cortex ◽  
Physiological Concentration ◽  
Pig Kidney ◽  
Glucose Carbon ◽  
Glutamine Synthesis ◽  
Stimulation Of

1. At a physiological concentration (5 mM), glucose was found to be metabolized by isolated kidney cortex tubules prepared from fed guinea pigs. 2. The release of 14CO2 from [U-14C]glucose indicated that oxidation of the glucose carbon skeleton represented about 50% of the glucose removed; significant amounts of lactate and glutamine also accumulated. 3. Addition of 0.1-10 mM NH4Cl led to a dose-dependent stimulation of glucose metabolism which was accompanied by a large increase in lactate and glutamine accumulation and, to a lesser extent, in glucose oxidation. 4. Comparison of the release of 14CO2 from [1-14C]- and [6-14C]glucose indicates that, in both the absence and the presence of NH4Cl, the pentose phosphate shunt was only a minor pathway of glucose metabolism. 5. The central role of pyruvate carboxylase in the conversion of glucose carbon into glutamine carbon was demonstrated by using a bicarbonate-free medium and measuring the fixation of 14CO2 from [14C]bicarbonate, which was recovered mostly at C-1 of glutamine plus glutamate. 6. The NH4Cl-induced stimulation of glucose removal was secondary not only to increased glutamine synthesis, as shown by the effect of methionine sulphoximine, an inhibitor of glutamine synthetase, but also to the stimulation of phosphofructokinase activity by NH4Cl. 7. Renal arterio-venous difference measurements revealed that, in vivo, the guinea-pig kidney removed glucose from the circulating blood, which suggests that glucose carbon may contribute to the carbon skeleton of the glutamine released by this organ.

Posttranscriptional upregulation of Na(+)-K(+)-ATPase activity in newborn guinea pig renal cortex

1997 ◽  
Vol 273 (2) ◽  
pp. F254-F263 ◽  
Author(s):  
E. N. Guillery ◽  
D. J. Huss ◽  
A. A. McDonough ◽  
L. C. Klein
Keyword(s):  
Guinea Pig ◽  
Atpase Activity ◽  
Renal Cortex ◽  
Specific Activity ◽  
Mrna Abundance ◽  
Beta Subunit ◽  
Protein Abundance ◽  
Developmental Patterns ◽  
Protein Levels ◽  
Subunit Mrna

We measured Na(+)-K(+)-adenosinetriphosphatase (Na(+)-K(+)-ATPase) activity and subunit abundance in renal cortical homogenates and basolateral membranes (BLM) from fetal, newborn, and adult guinea pigs. Pump specific activity increased four- to fivefold in cortical homogenates and BLM during the transition from fetus to newborn. Immunoblots of BLM showed that alpha- and beta-subunit abundance increased four- to seven- and fourfold, respectively, during the transition from fetus to newborn. Immunoblots of cortical homogenates revealed similar developmental patterns, with newborns having 3.5-fold (alpha) and 2.3-fold (beta) greater subunit abundances than fetuses. Therefore, the bulk of the postnatal increase in BLM-Na(+)-K(+)-ATPase abundance resulted from increased pump production or decreased pump degradation, rather than from redistribution of pumps from intracellular pools. Despite the developmental increase in alpha- and beta-subunit protein levels, newborn guinea pig kidneys had only 1.4- to 2.1-fold greater alpha 1-subunit mRNA abundance and only a 1.5-fold greater beta 1-subunit mRNA abundance than fetal kidneys. These results demonstrate large increases in renal cortical Na(+)-K(+)-ATPase specific activity and protein abundance immediately after birth. These increases, which appear to result largely from posttranscriptional upregulation, may play an important role in mediating the rapid postnatal increase in tubular NaCl reabsorption.

Dose-dependent cytochemical responses of the guinea pig renal cortex to femtogram quantities of bovine parathyroid hormone

1976 ◽  
Vol 22 (S1) ◽  
pp. 385-385 ◽  
Author(s):  
D. J. Chambers ◽  
J. M. Zanelli ◽  
J. Chayen ◽  
J. A. Parsons
Keyword(s):  
Parathyroid Hormone ◽  
Guinea Pig ◽  
Renal Cortex ◽  
Dose Dependent ◽  
Bovine Parathyroid Hormone

Investigation of a substance of renal origin which inhibits the growth of renal cortex explant in vitro

Development ◽  
1974 ◽  
Vol 31 (3) ◽  
pp. 655-665
Author(s):  
S. E. Dicker ◽  
Christine A. Morris
Keyword(s):  
Chick Embryo ◽  
Guinea Pig ◽  
Inhibitory Activity ◽  
Renal Cortex ◽  
Renal Medulla ◽  
Immune Serum ◽  
Supernatant Fluid ◽  
Serum Samples ◽  
Growth Inhibitory

(1) Explants of renal cortex from 7-day mice or 5-day rats were reared on plasma clots, in the presence or absence of chick embryo metanephros. (2) The size of outgrowth, estimated after 48 h, was similar for renal cortex of both species. When reared in chick embryo extract in the presence or absence of metanephros, the out-growth estimated after 48 h was 2·08±0·092 greater than that of the initial explant. (3) Addition of supernatant fluid from a homogenate of renal cortex of adult mouse, rat, guinea-pig, rabbit or pig inhibited the outgrowth of renal cortex explant from neonate mouse or rat. The supernatant fluid from a homogenate of adult renal medulla had no significant effect. (4) The inhibitory activity of the supernatant fluid from a homogenate of renal cortex from adult animals was destroyed by heating at 99 °C. (5) The compound with growth-inhibitory activity appeared to be cortex-specific but not species-specific. Extracts of liver, spleen, duodenum, and heart muscle of adult animals had no significant effect on the outgrowth of renal explants of neonate animals; and extracts from renal cortex of adult mammals had no significant effect on the growth of other tissues from neonate mice or rats. (6) The degree of growth inhibition was related to the amount of protein in the extract of renal cortex. Maximum inhibition was observed with extracts of renal cortex containing 2·5 mg protein/0·5 ml. (7) Immune serum samples were obtained from rabbits and guinea-pigs immunized against extracts of renal cortex and medulla and liver from rats and mice. Only the serum from either rabbit or guinea-pig immunized against extracts of renal cortex blocked the growth-inhibitory action of renal cortex extracts.

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