Carbohydrate metabolism gluconeogenesis

Carbohydrate metabolism gluconeogenesis is increased and peripheral glucose utilisation (transport across cell membranes) may be decreased (insulin antagonism) so that h5q>erglycaemia and sometimes glycosuria result. Latent diabetes becomes overt. 

Carbohydrate Metabolism Glycolysis/ Gluconeogenesis Citrate cycle (TCA cycle)... 

Fructose 2,6-bisphosphate (Fru-2,6-bP) plays an important part in carbohydrate metabolism. This metabolite is formed in small quantities from fructose 6-phosphate and has purely regulatory functions. It stimulates glycolysis by allosteric activation of phosphofructokinase and inhibits gluconeogenesis by inhibition of fructose 1,6-bisphosphatase. 

The effects of insulin on carbohydrate metabolism are discussed on p. 158. In simplified terms, they can be described as stimulation of glucose utilization and inhibition of gluconeogenesis. In addition, the transport of glucose from the blood into most tissues is also insulin-dependent (exceptions to this include the liver, CNS, and erythrocytes). 

To meet these changing circumstances, the liver has remarkable metabolic flexibility. For example, when the diet is rich in protein, hepatocytes supply themselves with high levels of enzymes for amino acid catabolism and gluconeogenesis. Within hours after a shift to a high-carbohydrate diet, the levels of these enzymes begin to drop and the hepatocytes increase their synthesis of enzymes essential to carbohydrate metabolism and fat synthesis. Liver enzymes turn over (are synthesized and degraded) at live to ten times the rate of enzyme turnover in other tissues, such as muscle. Extrahepatic... 

Glucocorticoid treatment of known diabetics normally leads to deregulation, but this can be compensated for by adjusting the dose of insulin. The increased gluconeogenesis induced by glucocorticoids mainly takes place in the liver, but glucocorticoid treatment is especially likely to disturb carbohydrate metabolism in liver disease. 

The biosynthetic reaction pathway to a compound is usually not a simple opposite of its breakdown. Chapter 12 of Volume 1 discusses this concept in regard to carbohydrate metabolism and gluconeogenesis. In fatty acid synthesis, acetyl-CoA is the direct precursor only of the... 

The carbon skeletons used for the synthesis of glucose are not of carbohydrate origin but are derived from particular amino acids. One exception to this is the carbon skeleton of lactate, itself a product of carbohydrate metabolism, which can be incorporated into a new glucose molecule. This process, the synthesis of new glucose from essentially noncarbohydrate precursors, is called gluconeogenesis. 

H Biotin Coenzyme in carboxylation reactions in gluconeogenesis and fatty acid synthesis role in regulation of cell cycle Impaired fat and carbohydrate metabolism dermatitis... 

Because the liver is a major processor of dietary and endogenous carbohydrates, liver disease affects carbohydrate metabolism in a variety of ways (see Chapter 25). However, none of the conventional modes of evaluating carbohydrate metabolism have value in the diagnosis of liver disease. Because the liver is the major site of both glycogen storage and gluconeogenesis, hypoglycemia is a common complication in certain liver diseases, particularly Reye s syndrome, fulminant hepatic failure, advanced cirrhosis, and hepatocellular carcinoma. 

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