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Liver Control Of Blood Glucose Notes

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This is an extract of our Liver Control Of Blood Glucose document, which we sell as part of our Biochemistry Notes collection written by the top tier of Oxford students.

The following is a more accessble plain text extract of the PDF sample above, taken from our Biochemistry Notes. Due to the challenges of extracting text from PDFs, it will have odd formatting:

Liver: regulation- maintainance of constant blood glucose concentration Sources of glucose in the blood
-Dietary- Carbohydrates
-Endogenous synthesis/ breakdown of endogenous stores Response to an increase in blood glucose after a meal
-Pancreas detects an increase in blood glucose concentrations - glucose enters through Glut2 transporters which transport glucose in proportion to the blood glucose concentrations- an increase in blood glucose absorbed into pancreatic beta cells- increases the ration of ATP/ADP and NADH/NAD+. This closes Katp channels which depolarises the cell- opens voltage gated calcium channels-depolarisationsecretion of insulin
-when insulin is released it acts on peripheral tissue which stimulates the uptake of glucose into cells. The amount of insulin released is proportional to the uptake of glucose
-liver: when there is an increase in blood glucose there is also a proportional increase in blood glucose transportation due to GLUT 2 transporters- increase in free glucose concentration acts as an allosteric inhibitor to glycogen phosphorylase and inhibits the break down of glycogen
-binding of insulin activates protein phosphatase and results in the complete inhibition of glycogen phosphorylase which results in the enzyme becoming unresponsive to allosteric inhibition. It also activates glycogen synthase
-excess substrates, amino acids, fructose and lactose are turned into glucose through gluconeogeneis and is stored as glycogen-this replenishes the endogenous stores. However the liver doesn't take up dietary glucose to store as glycogen directly Long period after meal: blood glucose concentration is LOW
-Glucagon is released by pancreas-activates protein kinase A- phosphorylates the glycogen phosphorylase kinase and glycogen phoshporylase-increased mobilisation of glycogen
-During excercise- adrenaline is released and also mobilises glycogen from the liver. After glycogen stores are depleted
-after glycogen stores are depleted gluconeogenesis occurs

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