Glucose production

Draw the structure of cyclic adenosine monophosphate (cAMP), a messenger involved in the regulation of glucose production in the body. Cyclic AMP has a phosphate ring connecting the 3 and 5 hydroxyl groups on adenosine. 

Metformin restrains hepatic glucose production principally by suppression of gluconeogenesis. The mechanisms involve potentiation of insulin action and decreased hepatic extraction of certain gluconeogenic substrates such as lactate. In addition, metformin reduces the rate of hepatic glycogenolysis and decreases the activity of hepatic glucose-6-phosphatase. Insulin-stimulated glucose uptake and glycogenesis by skeletal muscle is increased by metformin mainly by increased... 

Antidiabetic Drugs other than Insulin. Figure 3 The antihyperglycaemic effect of metformin involves enhanced insulin-mediated suppression of hepatic glucose production and muscle glucose uptake. Metformin also exerts non-insulin-dependent effects on these tissues, including reduced fatty acid oxidation and increased anaerobic glucose metabolism by the intestine. FA, fatty acid f, increase i decrease. 

There is weak expression of PPARy in muscle, liver and other tissues, enabling TZDs to support the effects of insulin in these tissues, notably increased glucose uptake in muscle and reduced glucose production in liver. TZDs may also affect nutrient metabolism by skeletal muscle through a direct mitochondrial action that is independent of PPARy. 

Biological actions Adipocyte differentiation fatty acid uptake lipogenesis glucose uptake other effects on nutrient metabolism which lower hepatic glucose production... 

Insulin resistance occurs when the normal response to a given amount of insulin is reduced. Resistance of liver to the effects of insulin results in inadequate suppression of hepatic glucose production insulin resistance of skeletal muscle reduces the amount of glucose taken out of the circulation into skeletal muscle for storage and insulin resistance of adipose tissue results in impaired suppression of lipolysis and increased levels of free fatty acids. Therefore, insulin resistance is associated with a cluster of metabolic abnormalities including elevated blood glucose levels, abnormal blood lipid profile (dyslipidemia), hypertension, and increased expression of inflammatory markers (inflammation). Insulin resistance and this cluster of metabolic abnormalities is strongly associated with obesity, predominantly abdominal (visceral) obesity, and physical inactivity and increased risk for type 2 diabetes, cardiovascular and renal disease, as well as some forms of cancer. In addition to obesity, other situations in which insulin resistance occurs includes... 

Insulin is a hormone manufactured by the beta cells of the pancreas. It is the principal hormone required for the proper use of glucose (carbohydrate) by the body. Insulin also controls the storage and utilization of amino acids and fatty acids. Insulin lowers blood glucose levels by inhibiting glucose production by the liver. 

Metformin sensitizes die liver to circulating insulin levels and reduces hepatic glucose production. 

Newsholme EA, Start C Regulation in Metabolism. Wiley, 1973. Nordlie RC, Foster JD, Lange AJ Regulation of glucose production by the liver. Annu Rev Nutr 1999 19 379. 

Alcohol Reduction Reduces hepatic glucose production... 

Since glycogen phosphorylase controls the rate of glucose production, the question is how signals from the brain or muscle are relayed to this enzyme. The signaling... 

Figure 7.2 Glucose regulation by insulin. Increased concentrations of glucose and amino acids in the circulation, vagus nerve stimulation and circulating hormones e.g. GLP) stimulate insulin secretion by 3-cells of the pancreatic islets. Insulin suppresses glucose production by the liver and increases glucose uptake by skeletal muscle and fat, leading to decreased circulating glucose concentrations.

As mentioned above, insulin secretion by p-cells of the pancreatic islets increases in response to increasing glucose concentrations. In the insulin-resistant state, despite insulin concentrations that are increased two- to three-fold, there is an excessive rate of liver-glucose production. In addition, skeletal muscle glucose disposal in response to insulin is markedly decreased. This results in increased glucose concentrations. This inability to control glucose concentrations, is referred to as impaired glucose tolerance and may ultimately lead to type-2 diabetes. 

Wolfe provided an excellent account of the systematic apphcation of stable and radioactive isotope tracers in determining the kinetics of glucose production, glyco-genolysis, and gluconeogenesis in living systems. 

Determine the flow rate of books which maximizes glucose production per word gobbled up, and find this production rate. 

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