wat role does the polyol pathway play in disturbances of carbohydrate metabolism?
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- toxisoftLv 41 decade agoFavorite Answer
Cells use glucose for energy and glucose not used for energy enters the polyol pathway if aldose reductase reduces it to sorbitol. This reaction oxidizes NADPH to NADP+. Sorbitol dehydrogenase can then oxidize sorbitol to fructose, which also produces an NADH from NAD+, and hexokinase can return the molecule to the glycolysis pathway by phosphorylating the fructose, to fructose 6 phosphate, but, in uncontrolled diabetics, who have high blood glucose, more than glycolysis can handle, the reaction's mass balance ultimately favors the production of sorbitol.
Activation of the polyol pathway results in a decrease of reduced NADP+ and oxidized NAD+; these are necessary cofactors in redox reactions throughout the body. The decreased concentration of these cofactors leads to decreased synthesis of reduced glutathione, nitric oxide, myoinositol, and taurine. Myo-inositol is especially required for the normal function of nerves. Sorbitol may also glycate nitrogens on proteins, like collagen, and these are known as AGEs, advanced glycation endproducts. AGEs are well known to cause pathology in the human body, one effect which is mediated by receptor mediators cytokines effects and the inflammatory responses induced, and are seen on the hemoglobin A1C tests performed on known diabetics to assess their levels of glucose control.Source(s): http://en.wikipedia.org/wiki/Polyol_pathway