Glutamine balance in metabolic acidosis as studied with the artificial kidney

Addae, S.; Lotspeich, WD

doi:10.1152/ajplegacy.1968.215.2.278

Cited by 14 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…liver) must accelerate to maintain their unaltered blood levels. An augmented hepatic release of glutamine has indeed been shown in dogs during dialysis, with or without induced metabolic acidosis (54). Further studies on the effect of hemodialysis on the amino acid release from muscle and liver in man appear warranted to characterize the regulation of nitrogen homeostasis in renal disease.…”

Section: Methodsmentioning

confidence: 96%

Hormone-fuel concentrations in anephric subjects. Effect of hemodialysis (with special reference to amino acids).

Ganda¹,

Aoki²,

Soeldner³

et al. 1976

J. Clin. Invest.

View full text Add to dashboard Cite

A B S T R A C T Arterial blood concentrations of insulin, glucagon, and various substrates were determined in six anephric subjects in the postabsorptive state and immediately after hemodialysis. Plasma glucose and serum insulin concentrations were normal, and declined during dialysis. Plasma glucagon was elevated and remained unchanged. There was moderate hypertriglyceridemia before dialysis, but this decreased significantly after administration of heparin just before the start of dialysis, and at the end of dialysis was lowered further into the normal range.Comparison of postabsorptive whole blood concentrations of amino acids with those in normal, healthy adults revealed striking differences. Glutamine, proline, citrulline, glycine and both 1-and 3-methyl-histidines were increased, while serine, glutamate, tyrosine, lysine, and branched-chain amino acids were decreased. The glycine/serine ratio was elevated to 300% and tyrosine/ phenylalanine ratio was lowered to 60% of normal.To investigate the potential role of blood cells in amino acid transport, the distribution of individual amino acids in plasma and blood cell compartments was studied. Despite a markedly diminished blood cell mass (mean hematocrit, 20.6+1.4%), there was no significant decrease in the fraction of most amino acids present in the cell compartment, and this was explained by increases of several amino acids in cellular water. None were decreased. Furthermore, during dialysis, whole blood and plasma amino acids declined by approximately 30% and 40%, respectively, whereas no sig-

show abstract

Section: Methodsmentioning

confidence: 96%

Hormone-fuel concentrations in anephric subjects. Effect of hemodialysis (with special reference to amino acids).

Ganda¹,

Aoki²,

Soeldner³

et al. 1976

J. Clin. Invest.

View full text Add to dashboard Cite

show abstract

“…Glutamine is transported back into neurons to be used for neurotransmitter synthesis. Glutamine is also used by renal epithelial cells for the generation of ammonia to compensate for metabolic acidosis (1,31). Apart from these roles, the metabolism of glutamine to lactate, or glutaminolysis, is one of the defining features of tumor cell metabolism (17,39).…”

Section: Sarojini Balkrishna Angelika Bröer Alice Kingsland and Stmentioning

confidence: 99%

Rapid downregulation of the rat glutamine transporter SNAT3 by a caveolin-dependent trafficking mechanism in Xenopus laevis oocytes

Balkrishna

Bröer

Kingsland

et al. 2010

American Journal of Physiology-Cell Physiology

View full text Add to dashboard Cite

The glutamine transporter SNAT3 is involved in the uptake and release of glutamine in the brain, liver, and kidney. Substrate transport is accompanied by Na(+) cotransport and H(+) antiport. In this study, treatment of Xenopus laevis oocytes expressing rat SNAT3 with the phorbol ester PMA resulted in a rapid downregulation of glutamine uptake in less than 20 min. PMA treatment of oocytes coexpressing SNAT3 and the monocarboxylate transporter MCT1 reduced SNAT3 activity only, demonstrating the specificity of the regulatory mechanism. Single or combined mutations of seven putative phosphorylation sites in the SNAT3 sequence did not affect the regulation of SNAT3 by PMA. Expression of an EGFP-SNAT3 fusion protein in oocytes established that the downregulation was caused by the retrieval of the transporter from the plasma membrane. Coexpression of SNAT3 with dominant-negative mutants of dynamin or caveolin revealed that SNAT3 trafficking occurs in a dynamin-independent manner and is influenced by caveolin. Although system N activity was not affected by PMA in cultured astrocytes, a downregulation was observed in HepG2 cells.

show abstract

“…Glutamine cycling is under complex metabolic and hormonal control, involving flux changes through both periportal glutaminase and perivenous glutamine synthetase [60,62,75,76,82,85]. This complex and simultaneous regulation of periportal breakdown and perivenous resynthesis of glutamine explains the controversial findings in earlier studies on the role of the liver in glutamine metabolism, which was either identified with net glutamine uptake or release or no net glutamine turnover at all [104][105][106][107].…”

Section: Intercellular Glutamine Cyclingmentioning

confidence: 99%

Nitrogen metabolism in liver: structural and functional organization and physiological relevance

Häussinger

1990

Biochemical Journal

316

166

View full text Add to dashboard Cite

INTRODUCTIONThe liver was identified early in the fundamental work of Hans Krebs [1,2] as having a particular role in urea and glutamine metabolism. At the acinar level, these pathways are embedded into a sophisticated structural and functional organization with metabolic interactions between different hepatocyte populations. This provided a new insight into the role of the liver in maintaining ammoniat and bicarbonate homeostasis under physiological and pathological conditions.The functional units of the liver are the so-called acini [3,4], which extend from the terminal portal venule along the sinusoids to the terminal hepatic venule. Periportal hepatocytes (near the sinusoidal inflow) can be distinguished from more downstream located perivenous hepatocytes (near the sinusoidal outflow), whereas the borderline between the periportal and the perivenous compartment is not defined in general anatomical terms. The definition used here is a comparative-functional one, and thus will depend on the metabolic pathways under consideration. This is because periportal and perivenous hepatocytes differ in their complement of enzymes and their metabolic functions ('functional hepatocyte heterogeneity' or 'metabolic zonation'). The size of a periportal or perivenous 'metabolic zone' is pathway-specific. Thus, for example, a periportal compartment exhibiting a certain metabolic function can overlap with a perivenous compartment which is characterized by another pathway. Several reviews have appeared on this subject [5][6][7][8][9][10][11], and the subacinar localization of various metabolic pathways is summarized in Table 1. This article focuses on the functional significance of liver parenchymal cell heterogeneity in nitrogen metabolism.

show abstract

Glutamine balance in metabolic acidosis as studied with the artificial kidney

Cited by 14 publications

References 0 publications

Hormone-fuel concentrations in anephric subjects. Effect of hemodialysis (with special reference to amino acids).

Hormone-fuel concentrations in anephric subjects. Effect of hemodialysis (with special reference to amino acids).

Rapid downregulation of the rat glutamine transporter SNAT3 by a caveolin-dependent trafficking mechanism in Xenopus laevis oocytes

Nitrogen metabolism in liver: structural and functional organization and physiological relevance

Contact Info

Product

Resources

About