Glucose cell uptake

Nutrient homeostasis cell uptake of glucose (especially important in adipose and muscle), amino acids (all cells) and fatty acids stimulation of glycolysis but inhibition of gluconeogenesis (liver), synthesis of glycogen (liver and muscle), triglyceride (liver and adipose) and protein (all cells) ... 

Fig. 8 Glucose derivatised at various position. No cell uptake of the labeled compounds was found...

They found other peculiarities when studying the transport of L-tryptophan in human freshly sampled red cells uptake could be resolved into linear and saturable components but upon infection or storage of red cells the linear component was substantially increased whereas the Kt and maximum velocity (Vmax) remained constant. (They also contended that the presence of parasitized red cells altered the permselectivity of uninfected red cells.) Further, the changes in the permselectivity of the P. falciparum-infected red cells was unaffected by p-chloromercuribenzoate (PCMB) and cytochalasin B, inhibitors for glucose transport, as well as DIDS and DNDS for anion transport, but was inhibited by phloretin, a modifier of the membrane dipole potential shown to block a variety of mediated and non-mediated transport mechanisms. Phloretin also inhibited the in vitro growth of P. falciparum. This work is reviewed in Ginsburg and Kirk, 1998. 

Altered metabolism in the muscles. Lack of insulin results in reduced muscle cell uptake of amino acids, fatty acids, and glucose, followed by deterioration of muscles. 

Showdomycin. Showdomycin (2-p-D-ribofuranosyhnaleimide) (7) is a maleimide C-nucleoside antibiotic synthesi2ed by S. showdoensis-, isoshowdomycin (8) and maleimycin (9) have also been isolated (1—6). Showdomycin is not phosphorylated by nucleoside kinase and is not a substrate for nucleoside phosphorylase. Once (7) enters the cell, it blocks the uptake of glucose and other nutrients. 

FIGURE 5.13 Two basic types of biological transport are (a) transport within or between different cells or tissues and (b) transport into or out of cells. Proteins function in both of these phenomena. For example, the protein hemoglobin transports oxygen from the lungs to actively respiring tissues. Transport proteins of the other type are localized in cellular membranes, where they function in the uptake of specific nutrients, such as glucose (shown here) and amino acids, or the export of metabolites and waste products. 

Glucose uptake T f GLUT 1 activity Many cells... 

The rate of mitochondrial oxidations and ATP synthesis is continually adjusted to the needs of the cell (see reviews by Brand and Murphy 1987 Brown, 1992). Physical activity and the nutritional and endocrine states determine which substrates are oxidized by skeletal muscle. Insulin increases the utilization of glucose by promoting its uptake by muscle and by decreasing the availability of free long-chain fatty acids, and of acetoacetate and 3-hydroxybutyrate formed by fatty acid oxidation in the liver, secondary to decreased lipolysis in adipose tissue. Product inhibition of pyruvate dehydrogenase by NADH and acetyl-CoA formed by fatty acid oxidation decreases glucose oxidation in muscle. 

GLUT 2 Liver, pancreatic B cell, small intestine, kidney Rapid uptake and release of glucose... 

In addition to the direct effects of hyperglycemia in enhancing the uptake of glucose into the liver, the hormone insulin plays a central role in regulating blood glucose. It is produced by the B cells of the islets of Langerhans in the pancreas in response to hyperglycemia. The B islet cells are freely permeable to glu-... 

The hydrolysis of zeaxanthin esters by a carboxyl ester lipase indeed enhanced both the incorporation of zeaxanthin in the micellar phase and uptake of zeaxanthin by Caco-2 cells. As mentioned earher, carotenoids can also be linked to proteins by specific bindings in nature and these carotenoid-protein complexes may slow the digestion process and thus make their assimilation by the human body more difficult than the assimilation of free carotenoids. Anthocyanins are usually found in a glycosylated form that can be acetylated and the linked sugars are mostly glucose, galactose, rhamnose, and arabinose. 

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