Glucose-sodium transport

The blood-brain barrier (BBB) forms a physiological barrier between the central nervous system and the blood circulation. It consists of glial cells and a special species of endothelial cells, which form tight junctions between each other thereby inhibiting paracellular transport. In addition, the endothelial cells of the BBB express a variety of ABC-transporters to protect the brain tissue against toxic metabolites and xenobiotics. The BBB is permeable to water, glucose, sodium chloride and non-ionised lipid-soluble molecules but large molecules such as peptides as well as many polar substances do not readily permeate the battier. 

Schiller LR, Santa Ana CA, Porter J, Ford-tran JS Glucose-stimulated sodium transport by the human intestine during experimental cholera. Gastroenterology 1997 112 1529— 1535. 

Non-ruminants possess several intestinal Na+-dependent saturable transport systems. These include the well-known sodium-glucose co-transporter (SGLT1), responsible for the active uptake of glucose, and it appears to be specific for cinnamic and ferulic acid and possibly for other hydroxy-cinammic acids [112]. 

Exceptions from Lipinski s rule, i.e., molecules of PSA values > 140 A2 are found to be actively absorbed by carrier-mediated transport systems (Wessel et al. 1998), as shown in Fig. 3. IB. As further detailed in Fig. 3.2, the intestinal epithelium expresses a number of such transport systems for amino acids, organic anions and cations, nucleosides, and hexoses. Among these systems are the apical sodium-dependent bile acid transporter (ASBT Annaba et al. 2007), the monocarboxylate transporter (MCT Halestrap and Price 1999), the sodium-D-glucose co-transporter (SFGT1 Kipp et al. 2003), and the nucleotide transporter SPNT1 (Balimane and Sinko 1999). In addition, the expression of a specialized transporter system for small peptides has been found in the intestinal epithelium with the di/tripeptide transporter, PepTl (Tsuji 2002), after previous functional studies by Hu et al. (1989), and the cloning of PepTl... 

Ader, R, Block, M., Pietzsch, S., Wolffram, S. (2001). Interaction of quercetin glucosides with the intestinal sodium/glucose co-transporter (SGLT-1). Cancer Lett., 162, 175-180. 

Oral rehydration therapy (ORT) with glucose-electrolyte solution is sufficient to treat the vast majority of episodes of watery diarrhoea from acute gastroenteritis. As a simple, effective, cheap and readily administered therapy for a potentially lethal condition, ORT must rank as a major advance in therapy. It is effective because glucose-coupled sodium transport continues during diarrhoea and so enhances replacement of water and electrolyte losses in the stool. 

Effect Each polymer has the same osmotic effect as a single glucose or amino acid molecule but markedly enhances nutrient-induced sodium transport when the polymer is broken apart at the villus cell surface. (Rapid uptake at the surface avoids an osmotic penalty.) Water and ions are returned to the blood quickly, and less of both are bst in the stool. 

Glucose-induced or amino acid-induced sodium transport... 

Paracellular pathways are major routes of ion movement. As ions, monosaccharides, and amino acids are actively transported, an osmotic pressure is created, drawing water and electrolytes across the intestinal wall. This pathway accounts for significant amounts of ion transport, especially sodium. Sodium plays an important role in stimulating glucose absorption. Glucose and amino acids are actively transported into the blood via a sodium dependent cotransport mechanism. Cotransport absorption mechanisms of glucose-sodium and amino acid-sodium are extremely important for treating diarrhea. 

During diarrhea, the small intestine retains its ability to actively transport monosaccharides such as glucose. Glucose actively carries sodium with water and other electrolytes. Because the WHO-ORS has a high sodium concentration, U.S. physicians have been reluctant to use it in well-nourished children. Yet controlled comparative studies describe more favorable results with the WHO-ORS than with parenteral fluids. Amino acids promote sodium transport and act as... 

Sodium-dependent D-glucose Phlorizin transport system 7. SPECIFIC PEPTIDES Phlorizin polymer 210... 

Scheen AJ (2015) Pharmacodynamics, efficacy and safety of sodium-glucose co-transporter type 2 (SGLT2) inhibitors for the treatment of type 2 diabetes mellitus. Drugs 75 33-59 Scheen AJ (2015) SGLT2 inhibition efficacy and safety in type 2 diabetes treatment. Expert Opin Drug Saf 14 1879-1904... 

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