Carrier‐mediated transport of riboflavin in the rat colon

Yuasa, Hiroaki; Hirobe, Masato; Tomei, Shigemitsu; Watanabe, Jun

doi:10.1002/1099-081x(200003)21:2<77::aid-bdd211>3.3.co;2-1

Cited by 9 publications

(9 citation statements)

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“…The absorption of riboflavin from foods takes place predominantly in the small intestine through an active carrier-mediated transport process (17,24,41). In addition, carrier-mediated absorption in the colon is thought to be important, because riboflavin is synthesized by bacterial metabolism in the colon (21,44). The high levels of hRFT1 in the small intestine and colon suggest that hRFT1 mediates the absorption of riboflavin at these sites (Fig.…”

Section: Discussionmentioning

confidence: 99%

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Identification and functional characterization of a novel human and rat riboflavin transporter, RFT1

Yonezawa¹,

Masuda²,

Katsura³

et al. 2008

American Journal of Physiology-Cell Physiology

129

101

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Section: Discussionmentioning

confidence: 99%

“…In vivo, in situ, and membrane vesicle experiments have elucidated the predominant role of carrier-mediated absorption in the intake of riboflavin by the small intestine and colon (4,7,17,21,24,34,41,44). In addition, the subject of riboflavin excretion has gained increasing attention.…”

mentioning

confidence: 99%

Identification and functional characterization of a novel human and rat riboflavin transporter, RFT1

Yonezawa¹,

Masuda²,

Katsura³

et al. 2008

American Journal of Physiology-Cell Physiology

129

101

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“…Absorption of free riboflavin mainly takes place in the proximal small intestine through a carrier-mediated, saturable transport process (Jusko and Levy, 1967;Rivier, 1973;Meinen et al, 1977;Merrill et al, 1981;Daniel et al, 1983;Said and Ma, 1994;IOM, 1998;Said and Ross, 2012). A carrier-mediated absorption of riboflavin is also present in the colon (Sorrell et al, 1971;Yuasa et al, 2000;Said and Ross, 2012). A small amount of riboflavin circulates via the enterohepatic system (Said and Ross, 2012).…”

Section: Intestinal Absorptionmentioning

confidence: 99%

Dietary Reference Values for riboflavin

Products¹,

Turck²,

Bresson³

et al. 2017

EFS2

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Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) derives dietary reference values (DRVs) for riboflavin. The Panel considers that the inflection point in the urinary riboflavin excretion curve in relation to riboflavin intake reflects body saturation and can be used as a biomarker of adequate riboflavin status. The Panel also considers that erythrocyte glutathione reductase activation coefficient is a useful biomarker, but has limitations. For adults, the Panel considers that average requirements (ARs) and population reference intakes (PRIs) can be determined from the weighted mean of riboflavin intake associated with the inflection point in the urinary riboflavin excretion curve reported in four intervention studies. PRIs are derived for adults and children assuming a coefficient of variation of 10%, in the absence of information on the variability in the requirement and to account for the potential effect of physical activity and the methylenetetrahydrofolate reductase 677TT genotype. For adults, the AR and PRI are set at 1.3 and 1.6 mg/day. For infants aged 7-11 months, an adequate intake of 0.4 mg/day is set by upward extrapolation from the riboflavin intake of exclusively breastfed infants aged 0-6 months. For children, ARs are derived by downward extrapolation from the adult AR, applying allometric scaling and growth factors and considering differences in reference body weight. For children of both sexes aged 1-17 years, ARs range between 0.5 and 1.4 mg/day, and PRIs between 0.6 and 1.6 mg/day. For pregnant or lactating women, additional requirements are considered, to account for fetal uptake and riboflavin accretion in the placenta during pregnancy or the losses through breast milk, and PRIs of 1.9 and 2.0 mg/day, respectively, are derived.

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“…Milk is a rich source of RF for human babies and mammal cubs, and thus efflux of RF from cells of the mammary gland into milk is also of vital importance. RF transport has been studied in many animal tissues, cells, and membrane vesicles, especially in the small intestine and colon (382,545). Renal transport is also very important (202,459).…”

Section: Animalsmentioning

confidence: 99%

Genetic Control of Biosynthesis and Transport of Riboflavin and Flavin Nucleotides and Construction of Robust Biotechnological Producers

Abbas

Sibirny

2011

Microbiol Mol Biol Rev

325

272

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SUMMARY Riboflavin [7,8-dimethyl-10-(1′- d -ribityl)isoalloxazine, vitamin B 2 ] is an obligatory component of human and animal diets, as it serves as the precursor of flavin coenzymes, flavin mononucleotide, and flavin adenine dinucleotide, which are involved in oxidative metabolism and other processes. Commercially produced riboflavin is used in agriculture, medicine, and the food industry. Riboflavin synthesis starts from GTP and ribulose-5-phosphate and proceeds through pyrimidine and pteridine intermediates. Flavin nucleotides are synthesized in two consecutive reactions from riboflavin. Some microorganisms and all animal cells are capable of riboflavin uptake, whereas many microorganisms have distinct systems for riboflavin excretion to the medium. Regulation of riboflavin synthesis in bacteria occurs by repression at the transcriptional level by flavin mononucleotide, which binds to nascent noncoding mRNA and blocks further transcription (named the riboswitch). In flavinogenic molds, riboflavin overproduction starts at the stationary phase and is accompanied by derepression of enzymes involved in riboflavin synthesis, sporulation, and mycelial lysis. In flavinogenic yeasts, transcriptional repression of riboflavin synthesis is exerted by iron ions and not by flavins. The putative transcription factor encoded by SEF1 is somehow involved in this regulation. Most commercial riboflavin is currently produced or was produced earlier by microbial synthesis using special selected strains of Bacillus subtilis , Ashbya gossypii , and Candida famata . Whereas earlier RF overproducers were isolated by classical selection, current producers of riboflavin and flavin nucleotides have been developed using modern approaches of metabolic engineering that involve overexpression of structural and regulatory genes of the RF biosynthetic pathway as well as genes involved in the overproduction of the purine precursor of riboflavin, GTP.

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Carrier‐mediated transport of riboflavin in the rat colon

Cited by 9 publications

References 0 publications

Identification and functional characterization of a novel human and rat riboflavin transporter, RFT1

Identification and functional characterization of a novel human and rat riboflavin transporter, RFT1

Dietary Reference Values for riboflavin

Genetic Control of Biosynthesis and Transport of Riboflavin and Flavin Nucleotides and Construction of Robust Biotechnological Producers

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