Transporters glucose transporter

Increased glucose transport Glucose transport into adipocytes is very sensitive to the concentration of insulin in the blood. Circulating insulin levels are elevated in the absorptive state, resulting in an influx of glucose into adipocytes (Figure 24.5, O). 

The small intestine contains a wide variety of transporters (amino acid transporters, oligopeptide transporters, glucose transporters, lactic acid transporters etc.) on the apical membrane of the epithelial cells, which serve as carriers to facilitate nutrient absorption by the intestine. On the basolateral membrane, the presence of amino acid and oligopeptide transporters has been demonstrated. Active transport mechanisms for di- and tri-peptides have also been demonstrated in the nasal and buccal epithelia. 

One of the functions of insulin is to stimulate the movement of glucose into cells. Only a limited number of tissues are sensitive to insulin, however, including the heart, skeletal muscle, and adipose tissue. Liver, kidneys, and brain are not sensitive to insulin, although they contain glucose transporters. Glucose transporters of insulin-sensitive tissues are normally stored in the microsomes... 

G. Muller and S. Wied, The sulfonylurea drug, ghmepiride, stimulates glucose transport, glucose transporter translocation, and dephosphorylation in insulin-resistant rat adipocytes in vitro. Diabetes,... 

The absorption of sulfonylureas from the upper gastrointestinal tract is faidy rapid and complete. The agents are transported in the blood as protein-bound complexes. As they are released from protein-binding sites, the free (unbound) form becomes available for diffusion into tissues and to sites of action. Specific receptors are present on pancreatic islet P-ceU surfaces which bind sulfonylureas with high affinity. Binding of sulfonylureas to these receptors appears to be coupled to an ATP-sensitive channel to stimulate insulin secretion. These agents may also potentiate insulin-stimulated glucose transport in adipose tissue and skeletal muscle. 

Transport proteins Elemoglobin Serum albumin Glucose transporter... 

Glucose Transport in Erythrocytes Occurs by Facilitated Diffusion... 

FIGURE 10.5 A model for the arrangement of the glucose transport protein in the erythrocyte membrane. Hydropathy analysis is consistent with 12 transmembrane helical segments. 

FIGURE 10.26 Glucose transport in E. coli is mediated by the PEP-dependent phosphotransferase system. Enzyme I is phosphorylated in the first step by PEP. Successive phosphoryl transfers to HPr and Enzyme III in Steps 2 and 3 are followed by transport and phosphorylation of glucose. Enzyme II is the sugar transport channel. 

Walmsley, A. R., 1988. The dynamics of die glucose transporter. Trends in Biochemical Sciences 13 226—231. 

Wheeler, T. J., and Hinkle, P, 1985. The glucose transporter of mammalian cells. Annual Review of Physiology 47 503-517. 

Gene activated Lipoprotein lipase fatty acid transporter protein adipocyte fatty acid binding protein acyl-CoA synthetase malic enzyme GLUT-4 glucose transporter phosphoenolpyruvate carboxykinase... 

Diabetes Mellitus Insulin Receptor Glucose Transporters ATP-dependent K+Channel PPARs... 

In addition to secretory cells, many non-secretory cells are capable of regulating exocytotic fusion of transport vesicles that are derived from endosomal precursors. For instance, vesicles enriched in plasma membrane transport proteins are incorporated in a regulated manner in order to alter metabolite fluxes. Examples include the glucose transporter GLUT-4 in muscle and fat tissues, a key element in the control of... 

Glucose transporters are integral membrane proteins that catalyze the permeation of sugars into cells, along or against a concentration gradient. 

Glucose transport activity is regulated through transcriptional and translational control of the GLUT proteins, through their activity, and through alterations of their intracellular distribution. Most importantly, the GLUT4 continuously cycles between an intracellular,... 

At present, the only available drug that stimulates glucose transport is insulin. Insulin increases the abundance of the GLUT4 in plasma membranes of adipose and muscle cells by its recruitment from intracellular storage sites (for a detailed description of its mechanism, see Chapter Diabetes Mellitus). 

Scheepers A, Joost HG, Schurmann A (2004) The glucose transporter families SGLT and GLUT molecular basis of normal and aberrant function. JPEN J Parenter Enteral Nub 28 364-371... 

Wood IS, Trayhurn P (2003) Glucose transporters (GLUT and SGLT) expanded families of sugar transport proteins. BrJNutr 89 3-9... 

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