Inhibition of the intestinal transport of uracil by hexoses and amino acids

Katgely, Bernhard W.; Bridges, Robert J.; Rummel, W.

doi:10.1016/0005-2736(86)90246-4

Cited by 7 publications

(3 citation statements)

References 24 publications

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“…The high levels of β-alanine and cytosine in the rat fecal samples suggest a higher presence of potential inhibitors of the uracil transporters in the jejunum of the rat, which actively transports uracil from mucosa to serum. It has been shown that phenylalanine, which was also increased in the rat fecal sample, acts as a fully competitive inhibitor of the uracil transporter . The degradation of uracil to β-alanine by certain intestinal bacteria may account for the relative higher levels of β-alanine found in rat feces. , …”

Section: Discussionmentioning

confidence: 97%

“…It has been shown that phenylalanine, which was also increased in the rat fecal sample, acts as a fully competitive inhibitor of the uracil transporter. 42 The degradation of uracil to β-alanine by certain intestinal bacteria may account for the relative higher levels of β-alanine found in rat feces. 43,44 Influence of Age/Time on the Fecal Metabolite Profile.…”

Section: Discussionmentioning

confidence: 99%

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Species Variation in the Fecal Metabolome Gives Insight into Differential Gastrointestinal Function

et al. 2007

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The metabolic composition of fecal extracts provides a window for elucidating the complex metabolic interplay between mammals and their intestinal ecosystems, and these metabolite profiles can yield information on a range of gut diseases. Here, the metabolites present in aqueous fecal extracts of humans, mice and rats were characterized using high-resolution (1)H NMR spectroscopy coupled with multivariate pattern recognition techniques. Additionally, the effects of sample storage and preparation methods were evaluated in order to assess the stability of fecal metabolite profiles, and to optimize information recovery from fecal samples. Finally, variations in metabolite profiles were investigated in healthy mice as a function of time. Interspecies variation was found to be greater than the variation due to either time or sample preparation. Although many fecal metabolites were common to the three species, such as short chain fatty acids and branched chain amino acids, each species generated a unique profile. Relatively higher levels of uracil, hypoxanthine, phenylacetic acid, glucose, glycine, and tyrosine amino acids were present in the rat, with beta-alanine being unique to the rat, and glycerol and malonate being unique to the human. Human fecal extracts showed a greater interindividual variation than the two rodent species, reflecting the natural genetic and environmental diversity in human populations. Fecal composition in healthy mice was found to change over time, which might be explained by altered gut microbial presence or activity. The systematic characterization of fecal composition across humans, mice, and rats, together with the evaluation of inherent variation, provides a benchmark for future studies seeking to determine fecal biomarkers of disease and/or response to dietary or therapeutic interventions.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Species Variation in the Fecal Metabolome Gives Insight into Differential Gastrointestinal Function

et al. 2007

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“…In addition, sodium-dependent nucleobas e transport has been reported in guinea pig ventricula r myocytes (Haddock 1995). a Haddock (1995), b Barros (1994), c Shayeghi et al (1999), d Griffith and Jarvis (1993), e Griffith and Jarvis (1994), f Washington and Giacomini (1995), g Bronk and Hastewell (1987), h Yuasa et al (1996), i Katgely et al (1986), j K m value. This may be partially attribute d to inter-species differences, but most studies have used rodent cells or tissues (rabbit, rat, opossum ) and many of these difference s are large enough to have functional implications.…”

Section: Nucleobas E Transporters In Mammalian Cellsmentioning

confidence: 99%

Nucleobase transporters

Koning

2000

Molecular Membrane Biology

119

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Purines and pyrimidines play a key role in nucleic acid and nucleotide metabolism of all cells. In addition, they can be used as nitrogen sources in plants and many microorganisms. Transport of nucleobases across biological membranes is mediated by specific transmembrane transport proteins. Nucleobase transporters have been identified genetically and/or physiologically in bacteria, fungi, protozoa, algae, plants and mammals. A limited number of bacterial and fungal transporter genes have been cloned and analysed in great detail at the molecular level. Very recently, nucleobase transporters have been identified in plants. In other systems, with less accessible genetics, such as vertebrates and protozoa, no nucleobase transporter genes have been identified, and the transporters have been characterized and classified by physiological and biochemical approaches instead. In this review, it is shown that nucleobase transporters and similar sequences of unknown function present in databases constitute three basic families, which will be designated NAT, PRT and PUP. The first includes members from archea, eubacteria, fungi, plants and metazoa, the second is restricted to prokaryotes and fungi, and the last one is only found in plants. Interestingly, mammalian ascorbate transporters are homologous to NAT sequences. The function of different nucleobase transporters is also described, as is how their expression is regulated and what is currently known about their structure-function relationships. Common features emerging from these studies are expected to prove critical in understanding what governs nucleobase transporter specificity and in selecting proper model microbial systems for cloning and studying plant, protozoan and mammalian nucleobase transporters of agricultural, pharmacological and medical importance.

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