Intestinal glucose transport: Evidence for a membrane traffic–based pathway in humans

Santer, René; Hillebrand, Georg; Steinmann, Beat; Schaub, J.

doi:10.1053/gast.2003.50009

Cited by 62 publications

(35 citation statements)

References 25 publications

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“…However, this model has been recently challenged by a number of researchers. At the basolateral membrane of enterocytes, recent observations suggest that there seem to exist two separate pathways for glucose exit from enterocytes: one that involves GLUT2 and another that requires glucose phosphorylation, transfer of glucose-6-phosphate into the endoplasmatic reticulum and release of free glucose into the blood [38,39]. Moreover, at the brush border membrane, several lines of evidence demonstrate that there are two types of glucose transport: one is a highaffinity, Na + -dependent, phloridzin-sensitive transporter (SGLT1), and the other is a low-affinity transporter that may, or may not, be Na + -dependent and phloridzin-sensitive [18][19][20].…”

Section: Discussionmentioning

confidence: 99%

Intestinal Permeability to Glucose after Experimental Traumatic Brain Injury: Effect of Gadopentetate Dimeglumine Administration

Santos

Gonçalves²,

Araújo³

et al. 2008

Basic Clin Pharma Tox

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Traumatic injuries are the leading cause of mortality in individuals aged 1-44 years, and brain injury significantly contributes to the outcome in nearly one half of all deaths from trauma. At the intestinal level, traumatic brain injury (TBI) induces profound effects, including gastrointestinal mucosa ischaemia and motility dysfunction. However, nothing is known concerning the effect of TBI on the intestinal absorption of glucose. Hence, the aim of this study was to investigate the effect of TBI on the intestinal absorption of glucose by investigating the effect of TBI on the jejunal mucosal-to-serosal apparent permeability (AP-to-BL P app ) to two glucose model substrates, 3

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Section: Discussionmentioning

confidence: 99%

Intestinal Permeability to Glucose after Experimental Traumatic Brain Injury: Effect of Gadopentetate Dimeglumine Administration

Santos

Gonçalves²,

Araújo³

et al. 2008

Basic Clin Pharma Tox

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“…However, there is an increasing evidence showing that GLUT2 may also mediate a diffusive component of intestine glucose absorption in the brush-border membrane [89,90]. Mutations of SGLT1 have been linked to a major defect in glucose and galactose absorption [91], but both a GLUT2-deficient patient [92] and GLUT2-null mice [93] displayed normal intestinal monosaccharide transport kinetics, suggesting the presence of a membrane traffic-based pathway in intestinal sugar absorption.…”

Section: Roles Of Glucose Transporters In Differ-ent Physiological Prmentioning

confidence: 99%

Functional Properties and Genomics of Glucose Transporters

Zhao

Keating²

2007

486

393

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Glucose is the major energy source for mammalian cells as well as an important substrate for protein and lipid synthesis. Mammalian cells take up glucose from extracellular fluid into the cell through two families of structurallyrelated glucose transporters. The facilitative glucose transporter family (solute carriers SLC2A, protein symbol GLUT) mediates a bidirectional and energy-independent process of glucose transport in most tissues and cells, while the Na + /glucose cotransporter family (solute carriers SLC5A, protein symbol SGLT) mediates an active, Na + -linked transport process against an electrochemical gradient. The GLUT family consists of thirteen members (GLUT1-12 and HMIT). Phylogenetically, the members of the GLUT family are split into three classes based on protein similarities. Up to now, at least six members of the SGLT family have been cloned (SGLT1-6). In this review, we report both the genomic structure and function of each transporter as well as intra-species comparative genomic analysis of some of these transporters. The affinity for glucose and transport kinetics of each transporter differs and ranges from 0.2 to 17mM. The ability of each protein to transport alternative substrates also differs and includes substrates such as fructose and galactose. In addition, the tissue distribution pattern varies between species. There are different regulation mechanisms of these transporters. Characterization of transcriptional control of some of the gene promoters has been investigated and alternative promoter usage to generate different protein isoforms has been demonstrated. We also introduce some pathophysiological roles of these transporters in human.

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“…Furthermore, the evidence from knockout animal models and from human subjects with mutated transporters argues against the presence of GLUT2 on the brush-border membrane. GLUT2 knockout mice, and individuals with inactivating mutations in GLUT2 (Fanconi-Bickel syndrome) do not have any demonstrable defect in intestinal glucose absorption (31,32) .…”

Section: Intestinal Glucose Transportmentioning

confidence: 99%

Glucose sensing and signalling; regulation of intestinal glucose transport

et al. 2011

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Epithelial cells lining the inner surface of the intestinal epithelium are in direct contact with a lumenal environment that varies dramatically with diet. It has long been suggested that the intestinal epithelium can sense the nutrient composition of lumenal contents. It is only recently that the nature of intestinal nutrient-sensing molecules and underlying mechanisms have been elucidated. There are a number of nutrient sensors expressed on the luminal membrane of endocrine cells that are activated by various dietary nutrients. We showed that the intestinal glucose sensor, T1R2 + T1R3 and the G-protein, gustducin are expressed in endocrine cells. Eliminating sweet transduction in mice in vivo by deletion of either gustducin or T1R3 prevented dietary monosaccharide-and artificial sweetener-induced up-regulation of the Na + /glucose cotransporter, SGLT1 observed in wild-type mice. Transgenic mice, lacking gustducin or T1R3 had deficiencies in secretion of glucagon-like peptide 1 (GLP-1) and, glucose-dependent insulinotrophic peptide (GIP). Furthermore, they had an abnormal insulin profile and prolonged elevation of postprandial blood glucose in response to orally ingested carbohydrates. GIP and GLP-1 increase insulin secretion, while glucagon-like peptide 2 (GLP-2) modulates intestinal growth, blood flow and expression of SGLT1. The receptor for GLP-2 resides in enteric neurons and not in any surface epithelial cells, suggesting the involvement of the enteric nervous system in SGLT1 up-regulation. The accessibility of the glucose sensor and the important role that it plays in regulation of intestinal glucose absorption and glucose homeostasis makes it an attractive nutritional and therapeutic target for manipulation.Intestine: Glucose sensor: Nutrient: Neuroendocrine: SGLT1The intestinal epithelium is lined with a single layer of epithelial cells that undergoes rapid and continuous renewal. The stem cell located near the base of the crypt of Lieberkühn gives rise to absorptive enterocytes, and three types of secretory cells; mucus producing goblet, Paneth and enteroendocrine. Paneth cells, which secrete antimicrobial peptides, digestive enzymes and growth factors, complete their differentiation at the crypt base. The other three epithelial lineages differentiate during a highly organised upward migration from the crypt to the villus tip where they are extruded into the intestinal lumen (1,2) . This process takes about 2-3 d in most species (3)(4)(5) . Enterocytes constitute the majority (90 %) of cells lining the villus (Fig. 1). They are involved in vectorial transport of nutrients from the lumen of the intestine to the systemic system. These polarised cells possess two distinct membrane domains, the apical (brush border) and basolateral. These membranes differ in structure, function and surface charges (6) ; properties that have facilitated their isolation in pure form as brush-border or basolateral membrane vesicles. Brush-border membrane vesicles have been used frequently for measurements of digestive enzyme...

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Intestinal glucose transport: Evidence for a membrane traffic–based pathway in humans

Cited by 62 publications

References 25 publications

Intestinal Permeability to Glucose after Experimental Traumatic Brain Injury: Effect of Gadopentetate Dimeglumine Administration

Intestinal Permeability to Glucose after Experimental Traumatic Brain Injury: Effect of Gadopentetate Dimeglumine Administration

Functional Properties and Genomics of Glucose Transporters

Glucose sensing and signalling; regulation of intestinal glucose transport

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